Over the past several weeks the Shin Bet security service has arrested 16 men on suspicion of running a Hamas headquarters in Jerusalem, the internal security organization said Tuesday.

Shin Bet said the Hamas members, who sought to increase the organization’s influence in and around the Al Aqsa Mosque and the Temple Mount, represented both a potential security threat and part of an ongoing Hamas effort to expand its sphere of influence beyond the Gaza Strip.

The involvement of Jerusalem residents in the activities of Hamas is against the law in Israel. It is also, the Shin Bet said in a statement, the gateway to terror activities. “The organization’s activists in Jerusalem, who begin as organizational activists, become an attractive draft pool for military Hamas actions, and constitute, over the years, the long arm of Hamas military infrastructure in the West Bank, the Gaza Strip and internationally, enabling serious terror attacks against Israeli civilians.”

The statement came as two East Jerusalem residents were indicted Tuesday at Jerusalem’s District Court for allegedly hatching a plot with al-Qaeda to carry out numerous terror attacks including suicide bombings at the US Embassy in Tel Aviv and Jerusalem’s International Convention Center, as well as the abduction of an IDF soldier.

Iyad Abu-Sara, 23, was accused of contact with a foreign agent, conspiracy to commit a crime and support of a terrorist organization. Rubin Abu-Najma, 30, was charged with conspiracy to commit a crime, manufacturing weaponry, arson and other offenses.

Abu-Sara and Abu-Najma were allegedly contacted by a Gaza-based al-Qaeda militant via Facebook and Skype and were drafted to carry out various attacks against targets in Israel. These were reportedly initiated on the direct orders of al-Qaeda head Ayman al-Zawahiri.

The two were arrested four weeks ago along with a third man, 21-year-old Ala Anam, who has yet to be indicted. According to information provided by the Shin Bet, Anam was also contacted by the al-Qaeda point man and allegedly laid plans to assemble a Salafist cell in the northern West Bank and to carry out attacks within Israel.

According to his indictment, Abu-Sara was to be sent for training in Syria and would then help facilitate the twin bombing attacks, using al-Qaeda operatives who would enter Israel with forged paperwork. The embassy attack would be carried out by two suicide bombers. At the convention center three men would blow themselves up and afterwards Abu-Sara himself would drive a truck bomb to the scene and detonate it.

The 23-year-old had also allegedly agreed to carry out a shooting attack on a bus heading from Ma’ale Adumim to the Dead Sea, shooting at its tires and then firing at fleeing passengers and rescue workers who arrived at the scene.

Abu-Najma allegedly planned to abduct an IDF soldier and hand him over to West Bank militants in order to negotiate his release. He is also accused of setting up a group which routinely hurled rocks and Molotov cocktails at Jews in the east Jerusalem neighborhood of Abu Tor.

US officials have downplayed the significance of the plot, with an official telling AFP that while the allegations were being taken seriously, the plans were probably “aspirational” rather than an immediate threat.

“The detainee probably said it but I don’t think we give a lot of credence to that,” the unnamed source said, though he added “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 has said that the civil war in Syria, a magnet for terror operatives throughout the Middle East, has deepened the roots of al-Qaeda and other like-minded organizations in the region. Those organizations, it said, are increasingly striving to link up with willing Palestinians in the West Bank and East Jerusalem in order to strike Israel and Western targets.

AFP contributed to this report.