In the southern Gaza Strip, witnesses said troops shot dead Tariq Abu al-Husayn, 39, a local leader of Hamas' military wing, in a clash which began at Brazil refugee camp when fighters attacked soldiers who entered the camp three days ago.
The deaths stoked tension already fuelled by the killing of three American security guards in a bomb attack on a US diplomatic convoy in Gaza, on Wednesday and highlighted the persistent violence bogging down peace efforts.
At an angry funeral attended by thousands, Hamas activists threatened to avenge Husayn's death with human bomb attacks against Israel, witnesses said.
Another Hamas member was killed in the Gaza' shootings in the southern Rafah district and a woman, 30, was killed by shrapnel from a tank shell after emerging from her house.
West Bank killing
In a separate clash on Saturday, soldiers shot dead a 16-year-old boy during a confrontation in the West Bank city of Tulkarm. Palestinian witnesses said the troops opened fire on stone-throwers, hitting the boy.
An Israeli military source said the soldiers had opened fire in response to shooting and the hurling of firebombs at them in Tulkarm, and that one of the gunmen was hit.
In Gaza, the source said, soldiers had opened fire on several armed men spotted laying an explosive in the Rafah area where Israeli soldiers had been searching the past week for tunnels allegedly used to smuggle weapons in from Egypt.
The source denied any tank rounds were fired in Gaza. Medics said 16 other Palestinians were wounded in that clash.
Thousands of angry Palestinians attended a funeral for the three Palestinians in Rafah on Saturday afternoon, where witnesses said fighters fired guns into the air and chanted:
"Our reaction will make Tel Aviv shudder ... All our bodies are ticking bombs."
Hamas' military wing also vowed revenge in a statement faxed to Reuters.
Israeli soldiers also blew up a home in Rafah on Saturday, witnesses said. United Nations personnel have said that more than 110 homes have been wrecked during the Israeli campaign in southern Gaza in the past week.
Nine Palestinians were wounded during exchange of fire in Rafah
More than 2180 Palestinians and about 830 Israelis have been killed in the Intifada, or Palestinian uprising for statehood, launched against Israel in September 2000. Hamas has carried out many of the bomb attacks in which Israelis have died.
Israel has blamed the violence on what it says is Palestinian President Yasir Arafat's failure to crack down on militant groups. Palestinians accuse Israel of stoking violence by pursuing a policy of tracking down and killing resistance group members.
Sharon downplays Arafat threat
Prime Minister Ariel Sharon appeared on Friday to rule out expelling Arafat, playing down an Israeli threat that had drawn an international outcry and US misgivings.
"Our calculations for years have been that expelling him would not be good for Israel," Sharon told the Jerusalem Post newspaper when asked about last month's security cabinet decision in principle to "remove" Arafat.
No group has taken responsibility for Wednesday's attack on the US convoy in Gaza. A US Federal Bureau of Investigation team and a Palestinian committee are investigating the bombing.
A senior US official said on Friday the US embassy had suspended travel for its diplomats to Gaza and ordered those already there to leave. The US consulate in East Jerusalem called on Americans visiting the West Bank to leave, he said.