Task: Question Understanding
Input (English): Passage: On 31 August, 2000, American citizen and Muslim convert Jeffrey Schilling from Oakland, California was captured on Jolo while visiting a terrorist camp with his new wife, Ivy Osani , whom he had met online. ASG demanded a $10 million ransom. Rebels also sarcastically threatened to behead him in 2001 as a "birthday present" to then Philippine President Gloria Macapagal Arroyo, who responded by declaring "all-out war" on them. The beheading threat was withdrawn after Schilling's mother, Carol, flew to the Philippines and appealed for mercy on local radio. On 12 April, 2001, Philippine soldiers raided a rebel camp and rescued the American. The United States praised the Philippine government for freeing Schilling. Many commentators have been critical of Schilling, who claims to have walked willingly into the camp after he was invited by his wife's cousin, a member of Abu Sayyaf. Schilling was one of more than forty hostages taken by Abu Sayyaf in 2000, including twenty-one tourists and workers seized in a raid on Sipadan diving resort in neighbouring Malaysia. Many of the hostages were released after Libya paid millions of dollars. A Libyan official stated that Schilling had visited the Jolo camp often before his capture. Philippine intelligence sources say he was interested in selling military equipment to the rebels, while the bandits accused him of being a CIA agent. Abu Sayyaf threatened several times to kill Schilling. At one stage, Schilling reportedly went on a hunger strike to win his freedom.
Question: What date were 21 tourists taken hostage by Abu Sayyaf?
Output (English): date