Both Israeli and Palestinian leaders have condemned an attack by an Israeli settler which left three Palestinians dead, urging calm as settlers withdraw.
Hamas chiefs say their fight will continue even after the withdrawal
Israel's Prime Minister, Ariel Sharon, said the killings were "a Jewish terror act" aimed at disrupting the pullout.
Israeli sources say the settler, a driver, shot dead three Palestinians workers as he was taking them home.
Palestinian leader Mahmoud Abbas appealed to militant groups not take any retaliation for the killings.
The incident took place as the driver was taking the men from an industrial area in the Shiloh settlement in the West Bank.
The man seized a gun at knifepoint from a security post and turned it on the Palestinians inside his car. Israeli sources say the gunman, who comes from a nearby Jewish settlement, has been arrested by police.
Mr Sharon said the shooting was "aimed against innocent Palestinians, out of twisted thinking, aimed at stopping the disengagement".
Earlier, militant group Hamas warned that it was considering taking action to avenge the deaths of the three Palestinians.
"This crime is not going to pass without tough punishment. The enemy is opening the gate of revenge," Hamas spokesman Mushir al-Masri said.
The BBC's Jim Fish in Jerusalem says the incident has cast a cloud over the ongoing operation to remove Israeli settlers from the Gaza Strip.
Earlier this month an Israeli soldier fired at random at passengers on a bus, killing four Israeli Arabs.
More than 50,000 police and soldiers are being used in Israeli's operation to pull out of 21 settlements in Gaza and four in the West Bank.