Damascus-based Palestinian militant leaders on Tuesday criticized the cease-fire declared by three major Palestinian groups, saying they would not join in any truce and may continue attacks against Israelis.

The militant Islamic Jihad (search) and Hamas (search) groups have announced a joint three-month truce with Israel after 33 months of violence. Palestinian Authority leader Yasser Arafat's Fatah faction has declared a six-month cease-fire.

But renegade offshoots, including the radical Damascus-based Popular Front for the Liberation of Palestine-General Command (search), have threatened to continue violence. Other factions said they would not join the declaration.

The declaration boosted efforts to implement the U.S.-backed "road map" for Israeli-Palestinian peace, which aims to end violence and establish a Palestinian state by 2005.

Ahmed Jibril, leader of the PFLP-GC, said his faction would keep conducting "resistance operations" against Israel.

"This declaration signed by Hamas, Islamic Jihad and Fatah (search) does not fulfill the minimum demands of the (Palestinian) uprising," Jibril said. "What it does is fulfill Israeli and American (security) demands."

"Our comrades and brothers inside (the Palestinian territories) ... will continue, through available means, to confront the Zionist enemy," he said.

The Palestinians should have demanded "a much greater price" in exchange for such a cease-fire, he said.

Maher Taher, a leader of the Damascus-based Popular Front for the Liberation of Palestine, criticized the Palestinian Authority's "monopoly" over decision-making and said his group would not join in any truce.

He stopped short of saying his group would violate the agreement.

"A cease-fire is something that should be discussed between all the factions through a united Palestinian leadership," he said.

"This is why we did not agree (to a truce) and consider ourselves unconcerned with this cease-fire. We are not a marginal force whose only role is to sign on a truce."

Jibril and Taher said they were in neighboring Lebanon during their telephone interviews with The Associated Press.

Officials of Damascus-based groups have been traveling to Lebanon for press interviews, apparently to avoid embarrassing the Syrian leadership which has come under pressure from the United States to stop supporting Palestinian militants.

Following his May visit to Syria, Secretary of State Colin Powell said Syrian President Bashar Assad had pledged to close down militant group offices that Damascus had hosted for years.

Taher said the road map to peace was aimed at ending the Palestinian uprising without giving anything substantial in return to the Palestinians.

"Israel wants to dismantle the infrastructure of the Palestinian resistance. They want to wipe out the intefadeh (uprising)," Taher said.

"This truce will not succeed."

One Damascus-based militant group, the Democratic Front for the Liberation of Palestine, has said in a statement that it accepted the truce.