Biden Says ‘The World Stands With You’ in Surprise Visit to UkraineU.S. President Joe Biden made an unannounced visit Monday to Ukraine, days ahead of the one-year anniversary of Russia’s invasion, saying he was there to “show our support for the nation’s independence, sovereignty and territorial integrity.” Speaking alongside Ukrainian President Volodymyr Zelenskyy at Mariinsky Palace in Kyiv, Biden announced $500 million in new U.S. aid, including artillery ammunition and anti-tank weapons. He also said there would be new U.S. sanctions against Russia this week but made no mention of the advanced weaponry, including fighter jets, that Zelenskyy is seeking from the United States and its Western allies. “One year later, Kyiv stands. And Ukraine stands. Democracy stands,” Biden said. “The Americans stand with you and the world stands with you.” Biden spoke about bringing together a coalition of more than 50 countries to help Ukraine’s military, and uniting leading economies to impose “unprecedented costs” on Russia’s economy. “Putin thought Ukraine was weak and the West was divided,” Biden said. “He thought he could outlast us. I don’t think he’s thinking that right now.” Zelenskyy thanked Biden for coming at a huge moment for Ukraine, and said he looked forward to discussing the battlefield situation with the U.S. leader. Air raid sirens were heard in Kyiv and elsewhere in Ukraine as Biden visited, including as he and Zelenskyy visited a cathedral in the capital. Biden and Zelenskyy also laid a wreath at a memorial wall dedicated to fallen heroes from the conflict. Biden was already scheduled to travel to the region, but the official White House schedule said he was not due to leave Washington until late Monday with Poland as his destination. The trip to Ukraine was shrouded in secrecy, which included Biden’s flight from Washington, a stopover at a U.S. military base in Germany, another flight to Poland and then a 10-hour train trip to Kyiv. SEE ALSO: In all, Biden was in Kyiv for about five hours, spending part of his time meeting with U.S. officials at the American Embassy. U.S. national security adviser Jake Sullivan said later that the U.S. had alerted Moscow ahead of Biden’s departure from Washington about the planned Ukrainian visit, “for deconfliction purposes" to avoid the possibility of an unintended lethal encounter between the two nuclear powers. Unlike some previous presidential visits to war zones in years past, the U.S. does not control the airspace over Ukraine, although U.S. warplanes monitored the Biden visit from the sky over Poland. Sullivan described Biden’s visit to Kyiv as historic, saying it was “unprecedented in modern times, to have the president of the United States visit the capital of a country at war where the United States military does not control the critical infrastructure.” Sullivan said that despite the need to surmount logistical issues for the trip, “President Biden felt that it was important to make this trip because of the critical juncture that we find ourselves as we approach the one-year anniversary of Russia’s full-scale invasion of Ukraine.” With the visit, he added, Biden wanted to send “a clear, unmistakable message of enduring American support for Ukraine. A clear unmistakable message of the unity of the West and the international community and standing behind Ukraine and standing up to Russian aggression.” The official White House schedule released Sunday included remarks from Biden Tuesday in Warsaw describing U.S. efforts to rally support for Ukraine and containing a pledge to continue to stand with the Ukrainian people. Biden was also due to meet with NATO Secretary-General Jens Stoltenberg and leaders of the Bucharest Nine group of countries before departing for Washington on Wednesday. These are the countries on NATO’s easternmost flank. Members of Biden's administration have visited Ukraine during the past year to meet with officials and show U.S. support, including Secretary of State Antony Blinken and Defense Secretary Lloyd Austin. Biden's wife, Jill, made an unannounced stop in Ukraine in May on Mother’s Day. SEE ALSO: Zelenskyy's first known wartime trip outside of his country was to the United States in December. Recently, he visited London, Paris and Brussels to meet with Western leaders. China aid The United States and European Union warned Monday of unspecified consequences should China provide lethal aid for Russian forces fighting in Ukraine. U.S. Secretary of State Antony Blinken told reporters there would be “real consequences” in U.S.-China relations and that he had shared the U.S. concerns directly with top Chinese foreign policy official Wang Yi. “I think China understands what’s at risk were it to proceed with providing that support to Russia,” Blinken said. He added that many other countries would take such military aid from China to Russia very seriously. Chinese foreign ministry spokesperson Wang Wenbin said at a briefing Monday that the United States is not in a position to make demands of China, and that China’s relations with Russia are based on “non-alignment, non-confrontation and non-targeting of third parties.” "It is the United States and not China that is endlessly shipping weapons to the battlefield,” Wang Wenbin said. European Union foreign policy chief Josep Borrell told reporters in Brussels that he had also discussed the situation with Wang Yi and asked him not to provide arms to Russia. Borrell said such Chinese aid “would be a red line in our relationship.” He spoke ahead of a meeting of EU foreign ministers and said Ukraine’s most urgent need is ammunition. Borrell said the ministers would discuss how to more quickly provide arms, especially ammunition, to Ukrainian forces. Some information for this story came from Agence France-Presse and Reuters.