JERUSALEM (AP) _ Israeli soldiers gunned down a Palestinian activist Tuesday, witnesses said, the fourth West Bank leader killed in a little over a month _ all considered political assassinations by the Palestinians.

Hours later, the pattern of nightly gunfire flared in the Gaza Strip, where the largest clash between Israeli soldiers and Palestinians in weeks killed two Palestinians and wounded at least 15 others.

The Israeli military said Palestinians near the Khan Yunis refugee camp in the southern part of Gaza opened fire on Israeli forces, who returned fire. It was the largest clash in the Gaza strip in weeks.

A Palestinian police spokesman said Israeli rocket fire hit the Palestinian police checkpoint at the entrance to the Khan Yunis refugee camp, killing Mahdi Ahmed Akilla, 35. The bullet-riddled body of another Palestinian was found at the camp, doctors at Khan Yunis hospital said. He was not immediately identified.

The doctors said 15 wounded had arrived at the hospital and ambulance crews were treating casualties at the camp.

Gunfire in the Gaza Strip has been a nightly occurrence for weeks now. On Tuesday, two Israeli women were wounded, one seriously, in a Palestinian attack near the isolated Jewish settlement of Morag. A school in an Israeli settlement near Khan Yunis also came under fire.

The killing on Tuesday of Yousef Abu Swayeh _ an activist in Palestinian leader Yasser Arafat's Fatah movement _ came as Israeli Prime Minister Ehud Barak, launching his re-election campaign, said he hoped conditions would soon be right for resuming peace negotiations with the Palestinians.

First, he said, violence must be substantially reduced.

In Morocco, U.S. Mideast envoy Dennis Ross held talks with Arafat into the early hours Wednesday, in an effort to find a way to restart peace talks.

Facing extreme criticism for the fighting, Barak resigned this weekend and new elections are scheduled for Feb. 6. Barak's rivals, the Likud, decided Tuesday to hold a primary election next week to pick a candidate to oppose him. The violence, which has left more than 310 people dead since Sept. 28, and Barak's response to it, are at the center of the campaign.

The Israeli military refused to comment on the killing of Abu Swayeh, nor would it confirm that he was even on its wanted list. But Deputy Defense Minister Ephraim Sneh told Israel radio earlier in the day that the only way to stop Palestinian attacks on Israelis is to ``strike at those who are leading the shooting cells and their deputies.''

Abu Swayeh, 27, was gunned down in front of his home in a village near Bethlehem, witnesses said, demanding anonymity. They said Israeli soldiers fired at him from a road under Israeli control and hit him with 17 bullets.

At least three other regional Palestinian leaders have been killed since the current unrest began. Israel took responsibility for two of the killings.

On Nov. 9, not far from where Abu Swayeh died, Israeli helicopters fired at a car carrying the local Fatah commander, Hussein Abayat, killing him and two women bystanders.

In the Gaza Strip on Nov. 23, Israeli forces opened fire on a car, killing a senior Fatah commander, Jamal Abdel Razek, and several of his aides.

Also on Nov. 23, a Hamas bombmaker, Ibrahim Bani Odeh, was killed in an explosion in his car. Israel denied it was involved, but a Palestinian court passed a death sentence against a Palestinian it ruled aided Israel in carrying out the assassination.

In Cairo, Egypt, the chairman of an international inquiry committee appointed by President Clinton said the group will not limit itself to reading reports and will gather evidence on the ground to determine the causes of the violence between Israel and the Palestinians.

``We'll receive information from the widest possible range of sources and we will make the appropriate judgment at the appropriate time on what is necessary,'' said former U.S. Sen. George Mitchell.