Israeli security forces announced Wednesday that they had foiled a global jihad plot to blow up the U.S. Embassy in Tel Aviv and Jerusalem’s Convention Center. But U.S. officials told NBC News they couldn’t confirm the threat, and hinted that the Shin Bet may even be misleading the Israeli government regarding the link between the cell and Al Qaeda.

The Shin Bet went public Wednesday with the arrests of three Palestinian Arabs who were captured a month earlier, and said that the suspects had been recruited by Al Qaeda over the Internet by an operative working for Ayman al-Zawahiri – the man who took over Al Qaeda after U.S. forces killed Osama bin Laden in May 2011.

Several US officials, however, told NBC News they hadn’t been able to verify the Israeli report — particularly the purported link to Al Qaeda — even though US and Israeli intelligence agencies communicate closely and frequently.

NBC said that the officials “noted that the arrests came three weeks ago and were only now being made public, for unknown reasons.”

Referring to the Israeli government, a senior State Department official, speaking on condition of anonymity, said, “We don’t have a reason to doubt that it’s information that they’ve been given.”

The question is whether the information is true, this official said, adding, “The validity is something we’re still looking at.”

The officials appear to be hinting that they suspect the Shin Bet of misleading its own government, for unclear reasons.

At a briefing for reporters in Washington, State Department spokeswoman Marie Harf also wouldn’t confirm the Israeli report, saying there were no plans to evacuate the Tel Aviv embassy because there was already “fairly high security at our facilities there.” US officials especially questioned the alleged link to Al Qaeda, telling NBC News the plot may merely have been “inspired” by the terrorist group, as opposed to directly ordered by its Pakistani-based leadership.

Shin Bet said one of the men it arrested disclosed plans to simultaneously bomb the U.S. Embassy in Tel Aviv and the International Convention Center in Jerusalem.

A total of three suspects have been arrested, all of whom are believed to have been recruited online as part of an Al Qaeda plot. They have been named as Iyad Khalid Abu Sara and Rubin Abu-Nagma, both in their twenties and from Jerusalem; and Ala Anam, a resident of the Palestinian Authority city of Jenin who is in his thirties.

The cell was apparently directed by a Gaza-based Al Qaeda operative named Arib Al-Sham.

According to the Shin Bet (Israel Security Agency), one of the plans was to carry out a suicide attack on a bus traveling from Jerusalem to Maaleh Adumim.

That attack would have involved firing at the bus’s tires first, in order to cause it to overturn. Then the terrorist was to murder the bus’s occupants at close range and await rescue forces, whom he would also fire at.

Another terrorist was to assist in carrying out a double suicide bombing at Jerusalem’s Binyanei Hauma Convention Center, as well as a bombing at the US Embassy in Tel Aviv.

Those attacks were to have been carried out by foreign terrorists who would arrive in Israel with forged Russian documents, disguised as tourists, according to the Shin Bet.