Four suspected Palestinian militants have been killed by an explosion in the Gaza Strip, Palestinian witnesses and medics say.
The cause of last night's explosion was unclear, but Israel and Palestinian militants had earlier traded threats of more attacks after undercover Israeli forces killed a senior Hamas commander in the West Bank on Saturday.
The weekend bloodshed further battered the "road map" peace initiative affirmed by Israeli Prime Minister Mr Ariel Sharon and Palestinian Prime Minister Mr Mahmoud Abbas at a June 4th summit with US President George W. Bush.
Witnesses initially said the four, initially identified as members of the al-Aqsa Martyrs Brigades - an armed offshoot of Palestinian President Yasser Arafat's Fatah national movement - were killed by Israeli tank rounds fired into Gaza's Beit Hanoun, a frequent flashpoint in the almost 33-month-old conflict.
Palestinian security sources and some witnesses reported tank fire, while other witnesses said the four were planting a bomb meant to detonate under a passing Israeli patrol but that it exploded prematurely.
Medics said all four bodies were dismembered.
But Israeli military sources said there was no Israeli army shooting in the area at the time. They said checks determined the dead militants were holding explosives that blew up in another case of what the army refers to as a "work accident".
Earlier, a 27-year-old Palestinian woman was shot dead by Israeli troops near the Jewish settlement of Morag in central Gaza, Palestinian medics said. Israeli military sources said troops shot at a suspicious person seen approaching Morag's perimeter fence.
US Secretary of State Colin Powell said after a meeting of the so-called Quartet of international mediators - the United States, Russia, the European Union and the United Nations - that the killing of Hamas's Mr Abdullah Kawasme could hinder peace.
The military wing of Hamas vowed "thundering retaliation" for Mr Kawasme's death and said a call by Mr Abbas for a truce was inconceivable while its men were being killed.