A US official downplayed on Thursday an announcement by the Shin Bet that it had uncovered an al-Qaida plot to attack the US Embassy in Tel Aviv, calling the cell’s plans “aspirational.”Nevertheless, the official did not rule out the possibility of danger.On Wednesday, the Shin Bet (Israel Security Agency) said it had arrested three Arab suspects – two from east Jerusalem and one from Jenin – who were preparing to bomb targets in Israel, including the embassy and the Jerusalem International 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 unnamed official as saying.While the United States was taking the allegations seriously, it had not yet confirmed any of the details, according to the official.“We can’t corroborate that; we probably don’t,” the official was quoted as saying. “We see it as what we would call an aspirational plot. It does not mean that it is not dangerous, it does not mean that it is not something we and Israel take seriously.”The Shin Bet identified the suspects in custody as Khalil Abu Sara, Ala Anam and Rubin Abu Nagma. They allegedly had been recruited by al-Qaida operative Ariv Al-Sham in Gaza.The security agency said Abu Sara and Abu Nagma were planning to provide explosive vests to foreign terrorists posing as Russian tourists for attacks on the Jerusalem International Convention Center and the US Embassy. It said they also were planning to kidnap a soldier and attack an Israeli bus in the West Bank. The two, who could travel freely in Israel because of their Jerusalem residency, were recruited via Facebook and Skype, the Shin Bet said in a statement, which added that Abu Sara had been arrested as he was preparing to travel to Syria via Turkey to undergo weapons training.The Shin Bet said Anam, from Jenin, was in custody on suspicion of planning to set up an al-Qaida cell in his area. Two of the detainees were arrested last month and the third this month, it said.Following the Wednesday announcement, US State Department deputy spokeswoman Marie Harf said that Washington had been in contact with Israel “regarding these threats.”“The US Embassy was not just the target, but other targets were mentioned, I believe,” she said.Harf added that the US had no plans to evacuate the mission.“We obviously don't discuss all of our security measures,” she said.Yaakov Lappin and Michael Wilner contributed to this report.