The militant Islamic group Hamas has threatened to target Jewish politicians after one of its leaders and founders was killed in an Israeli missile attack.
Ibrahim al-Maqadma was one of four Hamas members killed in the Gaza City strike which came hours after two Israelis were shot dead by Palestinians who infiltrated the settlement of Kiryat Arba, near Hebron in the West Bank.
Israel has intensified operations against Hamas in Gaza
The military wing of Hamas said it carried out the settlement raid late on Friday - another attack in an upsurge in violence between Palestinians and Israelis.
Tension also continued around the northern Gaza Strip town of Beit Lahiya where Israeli troops who imposed a security zone on Friday clashed with rioters, reportedly killing one Palestinian youth.
Following the death of al-Maqadma, Hamas official Abdel Aziz al-Rantissi called on all unit commanders to target Israeli politicians.
"Every so-called Jewish political leader is wanted because they are declaring war against God and Islam," he told Qatar-based al-Jazeera TV.
The fresh spate of killings comes as the Palestine Liberation Organisation's decision-making council is due to debate the creation of a new post of prime minister for the Palestinian Authority.
Palestinian leader Yasser Arafat has nominated his deputy in the PLO, Mahmoud Abbas, for the post. Mr Abbas has not yet accepted.
Mr Arafat said on Saturday that "Israeli occupation is the biggest obstacle standing in front of our reform process".
Tens of thousands of Palestinians turned out for al-Maqadma's funeral in Gaza City at which 30 men dressed in the bright green of Islam preceded the coffin, wearing signs to indicate that they were future suicide bombers.
"The Qassam brigades will cut off 100 heads in return for
the death of our martyr," supporters chanted through loudspeakers, referring to the military wing of Hamas.
The attack was the latest in a number of Israeli strikes against Hamas in Gaza, where for the past three weeks the Israeli army has been conducting a major operation to crush the militants.
The missile attack came after a Hamas attack on Jewish settlers
Last week, Israeli forces captured a co-founder of the Hamas movement, Mohammed Taha, during a raid on Gaza, in which several civilians were killed.
In recent days, Qassam rockets have been launched from Gaza across the boundary into Israel.
Three of the home-made rockets slammed into the town of Sderot on Thursday - there were no casualties.
Early on Friday, Israeli troops reoccupied part of the northern Gaza Strip, between Beit Lahiya and Beit
Hanoun, in an "open-ended" operation to stop such attacks.
Palestinian sources said that Israeli troops shot dead a 23-year-old Palestinian in Beit Lahiya on Saturday as youths stoned their tanks and bulldozers.
Friday's attack on the Kiryat Arba settlement occurred after the beginning of the Jewish Sabbath.
According to eyewitnesses, the gunmen slipped into the settlement disguised as Jewish seminary students.
They entered a family home and killed a husband and wife before troops arrived at the scene and shot them dead in turn.
Two other Palestinian militants who tried to infiltrate the nearby settlement of Negohot at the same time were killed. The Israel Defense Forces said they killed one of the two and the other died when an explosives belt he was wearing exploded.