RAMALLAH, West Bank -- U.S. Secretary of State Colin Powell met Yasser Arafat in the Palestinian leader's besieged headquarters on Sunday after failing to persuade Israel to end a crushing 16-day-old military assault on the West Bank, Reuters reported.

Witnesses said Arafat looked drawn as he greeted Powell in his office, with Palestinian bodyguards and armed agents of the U.S. Diplomatic Security Service standing by.

Neither man spoke to reporters who accompanied Powell to the bullet-pocked compound in the city of Ramallah where the Palestinian president has been confined by Israeli tanks.

Powell, aiming to halt 18 months of Israeli-Palestinian violence as a prelude to revived peace talks, had envisaged meeting Arafat on Saturday, but put the talks on hold after a suicide bomber killed six people in Bethlehem on Friday.

He went ahead with the meeting after Arafat met U.S. demands to condemn the attack and despite opposition from Israeli prime minister Ariel Sharon, who has sought to isolate Arafat and has said such talks would be a "tragic mistake".

A senior aide to Arafat said the Palestinian leader was ready to cooperate fully with Powell's peace mission as long as the United States prevailed on Israel to withdraw its troops immediately from Palestinian-ruled areas of the West Bank.

Asked if he thought Powell could reach a cease-fire deal with Arafat, Nabil Abu Rdainah told Fox television:

"The Israelis should withdraw immediately. That is the first step. If the Americans can guarantee this step, everything will happen smoothly later on."

But Powell, who met Sharon on Friday, has been unable to extract a commitment from him to order the army to withdraw immediately, as U.S. President George W. Bush first demanded on April 4, or by any specific date.

Asked if there was any deadline for ending the West Bank offensive, Brigadier-General Ron Kitrey, the Israeli army's chief spokesman, told army radio: "Of course not."

He said the mission to "uproot terror" would continue. "I suppose it would be naive to assume it is possible to eliminate it completely, but we can reduce its dimensions to a very great extent," Kitrey added.

As Israeli forces pressed on with their offensive, the army said a soldier shot dead an armed Palestinian on Saturday at a hostel next to Bethlehem's Church of the Nativity, where troops have been locked in a standoff with gunmen for 12 days.