Hundreds of Palestinian security officers arrived in Nablus on Friday in the first stage of a Western-backed drive to crack down on gunmen in the occupied West Bank ahead of a peace conference with Israel.

Israel, which is trying to bolster Palestinian President Mahmoud Abbas against his Hamas rivals, approved the deployment in the flashpoint West Bank city. Israeli government spokesman David Baker said the move would improve security and could be repeated elsewhere in the West Bank if it worked well.

Dressed in green berets and carrying new automatic rifles, 308 officers belonging to the Palestinian National Security Forces -- the equivalent of an army -- arrived in Nablus at dawn from a training centre in Jericho and some set up roadblocks.

The officers, who will be officially deployed in the next few days, provide a significant boost to a small police force that struggles to crack down on gunmen and gangs.

Prime Minister Salam Fayyad, who inspected the officers in a ceremony on Friday, told reporters it was the "starting point" of a broader drive "aimed at restoring the rule of law" in the Palestinian territories.

Israel seized control of West Bank cities handed over to the Palestinian Authority under the 1993 interim Oslo peace deal after the outbreak of the Palestinian uprising in 2000, and has since barred security forces from operating in the cities.

Although Palestinian police have been allowed to return to work recently, it is the first time that security forces have been allowed to operate in the West Bank since 2002.

Israel launches frequent raids against Palestinian militants in Nablus and controls entrance to the city through checkpoints, which it says are needed to stop suicide bombers.

Palestinians call Israel's network of West Bank checkpoints collective punishment. Palestinian government officials have expressed concern that continued raids by Israeli troops could jeopardize the experiment.

Several Nablus residents welcomed the arrival of the force.

"It is very good to have police and security forces to end the chaos in the town," said 22-year-old Tarek Hussein, a United Nations employee. "We hope Israel stops its raids into Nablus."

Abbas and Israeli Prime Minister Ehud Olmert are trying to narrow differences over establishing a Palestinian state ahead of a U.S.-backed Middle East peace conference expected to be held before the end of the year.

The United States has started training members of Abbas's Presidential Guard and National Security Forces. Last week the White House asked the U.S. Congress for at least $410 million in additional funds in 2008 to build up Abbas' forces and ease the Palestinian Authority's financial woes.

Islamist group Hamas routed Abbas's secular Fatah faction in violent clashes in Gaza in June. Abbas then sacked a Hamas-led government and appointed a Fatah-backed administration in the West Bank.

U.S. Secretary of State Condoleezza Rice meets Israeli and Palestinian leaders this weekend to craft a joint document ahead of the conference, to be held near Washington. (Additional reporting by Wafa Amr in Ramallah and Avida Landau in Jerusalem)