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 KUALA LUMPUR, Malaysia — When a Chinese government vessel took the world by surprise this month with its announcement that it had detected underwater signals that might have come from the missing Malaysia Airlines plane, China suddenly looked like the hero of the multinational search effort. 
 
 
 
 
 
 
 
 
 
 Within days, however, the Chinese claims were discounted, and attention shifted to another set of signals recorded by American personnel aboard an Australian ship hundreds of miles away. 
 
 Still, the Chinese claims have exasperated some officials from the United States and other participating countries. The announcement was only one in a series of moves by China that might have been intended to project competence, according to officials and analysts, but only served to distract and delay the search effort. 
 
 “Everybody wants to find the plane,” said a senior Defense Department official who spoke on the condition of anonymity because he did not want to appear overly critical of the Chinese. But, he continued, “false leads slow down the investigation.” 
 
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 Most of the passengers on board Malaysia Airlines Flight 370 were Chinese citizens, so the matter became a top priority for China. Since the plane’s disappearance on March 8, Beijing has deployed reconnaissance aircraft, more than a dozen vessels and, it said, 21 satellites in the search. Many of the ships in the current search zone, in the southern Indian Ocean, are Chinese. 
 
 The mission has clearly been a prime opportunity for the Chinese government to demonstrate its determination and technological abilities to its domestic audience, and to improve on its response to Typhoon Haiyan in the Philippines last year, which was widely criticized as late and tepid. 
 
 “This is a chance for China to regain some of its lost prestige and show the world what it’s capable of,” said Jeff Kingston, director of Asian studies at the Tokyo campus of Temple University. “There’s a lot of prestige on the line here.” 
 
 But the search has also brought China into sudden and close contact with regional competitors who have been uneasy with China’s rapid military expansion and its increasing willingness to project force across a wider area of the globe. With regional tensions already high before the plane disappeared, China’s rush to be first upset others involved in the search — not least because the Chinese turned out to be wrong. 
 
 In the first week of the search, China released satellite photographs purportedly showing wreckage in the South China Sea. The objects, however, turned out to be unrelated debris. The claim eventually elicited a rebuke from Malaysian officials that China had wasted the time of other nations looking for the missing Boeing 777-200. 
 
 On April 5, Chinese state-run news media reported that Haixun 01, a Chinese government search vessel apparently operating outside the zone designated that day by the search coordinators, had twice detected underwater signals that might have come from the missing plane’s flight recorders. 
 
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 Photographs published by the official Chinese news agency, Xinhua, showed crewmen using a hand-held hydrophone intended for use in shallow water, casting doubt on the value of the claims. 
 
 Still, search officials sent H.M.S. Echo, a British vessel equipped with highly sophisticated listening technology, to verify Haixun 01’s report. Several days later, Echo was quietly pulled from the area of the Chinese ship and sent to assist Ocean Shield, an Australian vessel also equipped with high-tech listening equipment that had detected four signals that search coordinators believed came from the plane’s flight recorders. 
 
 The delay in deploying Echo to join Ocean Shield may have cost searchers the opportunity to record more signals and narrow the underwater search area, officials say. 
 
 Willy Lam, a specialist in Chinese strategic policies at the Chinese University of Hong Kong, said that the lack of more sophisticated Chinese equipment was striking. 
 
 “According to the state propaganda, they are supposed to have sent the best they could muster, because it’s national prestige at stake, and they face a lot of pressure from the victims’ families,” Mr. Lam said. “In spite of all the hoopla over China building an advanced military, they seem to have not much to show in this operation.” 
 
 In an interview, a high-level official in the Malaysian government stiffened when Chinese involvement in the search arose. “Really helpful, aren’t they?” he said sarcastically. 
 
 Several analysts said that Beijing was under intense pressure to show its domestic audience that it was not only in the forefront of the search effort but also the most productive. 
 
 “The question is, Who delivered first?” said Carl Thayer, professor of politics at University of New South Wales in Australia. 
 
 The Chinese Foreign Ministry did not respond Monday to messages seeking comment on the search. 
 
 The international response to China’s missteps might not have been so negative had China been less critical of Malaysia’s handling of the investigation, analysts said. For weeks, the Chinese authorities and the state-run Chinese news media hectored the Malaysian government and demanded more transparency and information sharing. 
 
 Despite China’s clumsy execution, few observers question the government’s commitment to finding the plane. 
 
 “The scope, scale and expense of Chinese operations exceeds anything that China has undertaken to date,” said Jonathan D. Pollack, senior fellow in foreign policy at the Brookings Institution. “The Chinese are at least as intent on achieving definitive results as anyone else.” 
 
 “It’s possible that this has led some Chinese personnel to reach premature judgments based on limited or inconclusive observations,” Mr. Pollack said. “But this hardly seems unique to China.” ||||| Media playback is unsupported on your device Media caption The robotic submersible Bluefin-21 exceeded its depth safety limit, as Phil Mercer reports from Perth 
 
 A robotic submarine deployed to search for the missing Malaysia Airlines plane in the southern Indian Ocean has had its first mission cut short. 
 
 The Bluefin-21 was sent to search the sea floor for wreckage after signals believed to be consistent with "black box" flight recorders were detected. 
 
 But the drone exceeded its operating limit of 4,500m (15,000ft) and was brought back to the surface. 
 
 It was due to return later on Tuesday if weather conditions permitted. 
 
 "To account for inconsistencies with the sea floor, the search profile is being adjusted to extend the sonar search for as long as possible," an update from the US Navy - which operates the Bluefin-21 - said. 
 
 Flight MH370 went missing on 8 March with 239 people on board. It was flying from Kuala Lumpur to Beijing when it lost contact with air traffic controllers over the South China Sea. 
 
 Malaysian officials believe, based on satellite data, that it ended its flight thousands of kilometres off course, in seas west of the Australian city of Perth. 
 
 Media playback is unsupported on your device Media caption US Navy Captain Mark Matthews says the search had to be aborted due to a programming "oversight" 
 
 'Operating depth' 
 
 Amid a major international search, an Australian navy vessel last week detected four acoustic signals using a US Navy towed pinger locator. Officials believe these could come from the missing plane's flight recorders. 
 
 No signals have been detected since 8 April, however, leading to fears that the recorders' batteries - which last about a month - have run out. 
 
 On Monday, Air Chief Marshal Angus Houston, who heads the agency co-ordinating the search, said it was time to deploy the Bluefin-21 to begin its search of the sea floor. It set off on its first mission on Monday night. 
 
 "After completing around six hours of its mission, Bluefin-21 exceeded its operating depth limit of 4,500m and its built in safety feature returned it to the surface," the Joint Agency Co-ordination Centre said in a statement. 
 
 "Bluefin-21 is planned to redeploy later today when weather conditions permit." 
 
 The US Navy said in a later update that no objects of interest were found when the six hours of data were downloaded and analysed. 
 
 MH370 - Facts at a glance 8 March: Malaysia Airlines Kuala Lumpur-Beijing flight carrying 239 people disappears 
 
 Malaysia Airlines Kuala Lumpur-Beijing flight carrying 239 people disappears Plane's transponder, which communicates with ground radar, was switched off as it left Malaysian airspace 
 
 Satellite 'pings' indicate plane was still flying seven hours after satellite contact was lost 
 
 24 March: Based on new calculations, Malaysian PM says "beyond reasonable doubt" that plane crashed in southern Indian Ocean with no survivors What we know Deep sea challenge 
 
 Bluefin-21 is an almost 5m-long vehicle that can create a sonar map of the sea floor. On Monday officials said each mission was expected to last 24 hours, with 16 hours spent on the ocean floor, four hours' diving and resurfacing time, and four hours to download data. 
 
 The submersible has a safety feature that brings it to the surface if it exceeds its performance capabilities, however. 
 
 The sea where the Bluefin-21 is searching is estimated to be about 4,500m deep, but experts say there could be variations on the sea floor. 
 
 Australian officials have said previously that they are confident they are searching in the right area for the missing plane. 
 
 But ACM Houston warned on Monday that the search of the sea floor could be a long, painstaking process that might not yield results. 
 
 He said that other, larger vehicles that could go deeper than the Bluefin-21 were being looked into, but it depended on "the outcome of what we find when we go down and take a look". 
 
 Officials have no idea yet why the plane diverted so far from its intended flight path. Investigators are looking at options including hijacking, mechanical failure, sabotage and pilot action. 
 
 Recovering the flight recorders is seen as key to understanding what happened to the plane.
– Yet another setback in the search for Flight 370: The first undersea mission to search for the Malaysia Airlines jet, scheduled to last 16 hours, was cut short after the Bluefin-21 underwater drone exceeded its 2.8-mile operating limit, authorities say. The drone collected around six hours of footage yesterday, which did not provide any clues, Reuters reports. Its sonar search is concentrating on a zone of around 230 square miles of Indian Ocean seabed, and authorities say it could take months to scan the entire area. The Australian official in charge of the search says the Bluefin-21 has been redeployed and other vehicles capable of going deeper could be deployed depending on what the drone spots, reports the BBC. That might have to be the case: The US Navy captain handling Bluefin-21 says that if the drone goes past its depth limits one more time, it will effectively be rendered useless. "It could probably go down further than that once, but it wouldn’t be functional after that," he told the Guardian Australia, noting that while its "speed of deployment" gave the Bluefin-21 an edge, "it’s certainly not the tool I would use to do a very, very broad area sonar scan." The New York Times, meanwhile, looks at China's role in the search and finds that the country's eagerness to show off its technological abilities may only have delayed finding the aircraft. Officials involved with the search say that while China is certainly committed to the search, false leads from its ships and satellites ended up wasting valuable days.