A cache of weapons discovered hidden in caves in the West Bank has raised extra alarm bells among Israel's internal intelligence service because the terrorists are Jewish extremists.

The weapons were stolen from the army by members of the same movement that tried to blow up an Arab girls' school in Jerusalem two years ago using a trailer packed with explosives.

Now the head of Israel's Shin Bet Security Service (search) is warning the rise of extremism on the far right in Israel could lead to the assassination of Prime Minister Ariel Sharon, to stop his plan to withdraw Jewish settlements from Gaza.

Israel's minister for internal security has issued a warning that Jewish extremists are again planning to attack mosques in the hopes of igniting a war and halt any peace process.

Itamar Ben Gvir is one of the leaders of the outlawed Kach Movement (search) — followers of the radical Rabbi Meir Kahane. The posters in their office call for expelling the Arabs from Israel. This Jewish group with an office in downtown Jerusalem is listed both in Israel and the United States as a terror group.

Kach's "summer camps" for Jewish teenagers teaches them how to attack soldiers, evade army roadblocks, retake their homes if the army tries to evacuate them and survive police interrogations.

"I have no doubt that an Israeli who gives away parts of the land of Israel is a traitor and Ariel Sharon is a traitor," said Itamar Ben Gvir. "If someone is performing acts against the people of Israel — it is OK to kill him."

Click on the video box at the top of this story to watch a report by FOX News' Jennifer Griffin.