A US official downplayed on Thursday a Shin Bet announcement of an uncovered al-Qaida plot to attack the American Embassy in Tel Aviv. On Wednesday, the Shin Bet (Israel Security Agency) said it had arrested three Palestinian suspects - two from east Jerusalem and one from the West Bank city of Jenin - who were preparing to bomb multiple targets in Israel, including the US mission and the Jerusalem Convention Center. 'The detainee probably said it but I don't think we give a lot of credence to that. We don't have anything to prove it,' AFP quoted the official as saying. Yaakov Lappin contributed to this report.