The al-Aqsa Martyrs Brigades have not joined the truce
Israeli troops have shot dead a Palestinian militant in the West Bank city of Qalqilya.
The army said the man, who belonged to the al-Aqsa Martyrs' Brigade and was armed, was killed while trying to evade capture.
But Palestinian officials said he was wounded during the exchange of fire, and then killed after being detained.
Also on Thursday, Israel released the head of the Gaza Strip security services, Suleiman Abu Mutlak, who had been held in administrative detention since May.
The release of prisoners is a key Palestinian demand, included in the ceasefire declarations of the three main Palestinian militant organisations.
Earlier, Israeli forces closed the main road in the Gaza Strip for several hours, after a rocket attack on an Israeli settlement in which three people were wounded.
ROADMAP MAIN POINTS
Phase 1 (to May 2003): End to violence against Israelis and Palestinians; Palestinian political reform; Israeli withdrawal and freeze on settlement expansion; Palestinian elections
Phase 2: (June-Dec 2003) Creation of an independent Palestinian state; international conference and international monitoring of compliance with roadmap
Phase 3 (2004-2005): Second international conference; permanent status agreement and end of conflict; agreement on final borders, Jerusalem, refugees and settlements; Arab states to agree to peace deals with Israel
The Israelis blamed the attack on Palestinian militants and issued a formal protest to the Palestinian Authority.
The road had been officially re-opened to Palestinian traffic on Monday after being closed for more than two years.
Palestinian Prime Minister Mahmoud Abbas - also known as Abu Mazen - condemned the rocket attack, along with the recent shooting of a foreign worker in the West Bank, as "sabotage operations" which the Palestinian Authority would not accept.
The rocket attack happened just hours after Israeli troops pulled out of the West Bank town of Bethlehem, amid signs of progress towards an end to violence between the two sides.
The al-Aqsa Martyrs' Brigades, which shot dead a Bulgarian worker in the West Bank on Monday, has not accepted the ceasefire declared by three other Palestinian militant groups - Hamas, Islamic Jihad and Fatah.
The BBC's David Chazan says the group is made up of small localised units and there is little central control.
Israeli troops pulled out of northern Gaza on Sunday under a deal in which Palestinian security forces pledged to stop attacks by militants in that territory.
And Palestinian security forces have returned to Bethlehem for the first time since Israeli troops poured into the town after a suicide bombing in Israel last November.
Cheering residents applauded members of the security forces as they moved back into the town.
But travel into and out of Bethlehem will continue to be restricted by Israeli forces, who have remained in position outside the town.
US President George W Bush praised Israel's withdrawal in a phone call with Israeli Prime Minister Ariel Sharon, a White House spokesman said.
The US has also announced a $30m aid package to the Palestinian Authority to help rebuild infrastructure destroyed during Israeli incursions into the West Bank and Gaza Strip.
This resumption of direct US economic aid comes after years in which Washington only provided assistance to the Palestinians through the UN and private groups.
Abu Mazen said the withdrawals from Gaza and Bethlehem would be "followed by pullbacks from the rest of the cities and towns and Palestinian refugee camps".
However, Israeli Defence Minister Shaul Mofaz told the cabinet on Wednesday that Palestinian militant groups would have to be disarmed before Israel would pull out of any other Palestinian areas, officials said.