BEIRUT, July 13: The Palestinian militant groups Hamas and Islamic Jihad warned on Sunday they would end a truce they announced last month with Israel if the Palestinian Authority continued what they called a campaign to disarm them.

“The Palestinian security forces decided to start a campaign aimed to disarm the resistance...We warn that such an act...will make us think seriously of going back on our initiative of halting the military attacks (against Israel),” the two groups said in a joint statement faxed to Reuters.

“The Zionist enemy will bear the responsibility...so will the Palestinian Authority if it continues in any move against the resistance forces and its weapons,” the statement said.

The statement by the two largest Palestinian militant groups said that disarming them was “a red line and we will never accept trespassing it in any way.”

Leading Palestinian militant groups called a truce halting attacks on Israelis late last month. Washington welcomed the move but said the “terrorist infrastructure” of the groups must still be dismantled.

Israeli Prime Minister Ariel Sharon has demanded that new Palestinian Prime Minister Mahmoud Abbas begin to dismantle militant groups before further Israeli withdrawals from Palestinian areas take place under the U.S.-backed “road map” peace plan.

Abbas has said that a crackdown on militants — behind suicide attacks on Israelis since the uprising for independence erupted in September, 2000 — could lead to a Palestinian civil war.

Meanwhile, Abbas called on Israel to let President Yasser Arafat travel freely, as Israeli premier Ariel Sharon lobbied for his further isolation.

Israel and Washington are concerned Arafat is trying to weaken the peace efforts of Mr Abbas, who came under further pressure on Sunday when militants threatened to abandon a truce he negotiated if Palestinian forces went ahead with a campaign to disarm them.

Mr Sharon flew to Britain for a three-day visit where he planned to raise the issue of Arafat’s isolation in talks with British Prime Minister Tony Blair.

“Every phone call to Arafat...every dignitary that visits from the European Union, from Britain, only strengthens Arafat in his effort to scuttle and undermine Abbas’s position,” a senior Israeli official said ahead of the visit.

In response, Mr Arafat said he had withstood previous Israeli attempts to isolate him and would withstand this one too.

WIDENING RIFT: Mr Abbas, despite the widening rift with Arafat, said he raised Arafat’s freedom of movement with Russian Foreign Minister Igor Ivanov during talks on issues related to the peace plan.