Shin Beth chief Avi Dichter on Tuesday told the foreign affairs and defence committee of the Israeli parliament that hardliners might also open fire on security forces during the planned evacuation of the Gaza Strip's 8000 settlers.
"Right-wing extremists have not given up on the idea of attacking Jerusalem's Haram al-Sharif - Islam's third holiest site," Dichter said.
Asked by a committee member why the Shin Beth had made no arrests, he said agents did "not have sufficient proof".
Dichter said he did not expect the number of those involved in armed resistance to the enforced pullout to exceed a few dozen.
Military intelligence chief General Aaron Farkash gave a similar warning in October of a new attempt to blow up the Haram al-Sharif as the Gaza pullout neared.
In the early 1980s, Jewish hardliners attempted to blow up the revered site in a bid to derail Israel's withdrawal from the Sinai peninsula under the Camp David peace accord with Egypt, but the plan was apparently foiled by the Shin Beth.
Al-Haram al-Sharif, meaning the Noble Sanctuary, encompasses the Dome of the Rock and al-Aqsa mosque, and is known to Jews as the Temple Mount. The site is important to all three faiths including Christians.