(IsraelNN.com) Security forces have gone on alert for a possible terrorist attack in Jerusalem. Based on intelligence information, terrorists may already be in the city, seeking a target for an attack.

In Gush Etzion, the highest alert was declared after a truck filled with terrorists attempted to enter one of the communities there and was rebuffed, according to unconfirmed reports.

Motorists are advised that traffic is jammed in the northern parts of the city, where checkpoints have been set up.

Both alerts come several days after Israel removed 50 roadblocks and barriers throughout Judea and Samaria in response to pressure from US Secretary of State Condoleezza Rice.

The American Secretary has demanded that Israel ease restrictions on travel by Palestinian Authority Arabs despite an escalation of rock, firebomb and shooting attacks on Jewish drivers.

Hana Levi Julian contributed to this report