Israeli troops shot to death Friday four Palestinians in the occupied West Bank in clashes that broke out during a funeral for a Palestinian teenager, Arab doctors said.

The confrontations came as the United States and the PLO prepared for their first direct talks following PLO chairman Yasser Arafat's renunciation of terrorism and recognition of Israel's right to exist.At least 19 Palestinians were wounded, three critically, during clashes in the West Bank city of Nablus, city hospital officials said. Four Palestinians suffered gunshot wounds in villages near Tulkarem in clashes with troops after prayers, Arab witnesses said. One youth was wounded in the Gaza Strip refugee camp of Rafah, Gaza hospital officials said.

An army spokeswoman confirmed three fatalities and said the army was aware of the report a fourth Palestinian was killed but could not confirm it.

"There were violent disturbances all over Nablus, and several demonstrations were obviously planned ahead of time," a spokeswoman said, adding that it appeared stones and tires were stacked in preparation.

The army clamped a curfew on Nablus, the West Bank's largest city, to curb rioting.

The clashes were sparked by the death Thursday night of 15-year-old Ashraf Al Haj Daoud, who died of a gunshot wound suffered during clashes Nov. 25, doctors at Nablus' Anglican Hospital said.

The youth's brother was one of those injured Friday, officials said. The deaths raised to 328 the number of Palestinians killed in the yearlong Palestinian revolt against Israeli occupation of the West Bank and Gaza Strip. Thirteen Israelis have died.

Nablus residents declared an impromptu general strike to protest the teenager's death.