Israeli troops shot dead two Hamas commanders in the West Bank on Friday, in a raid against militants Israel blamed for the killing of four Jewish settlers a month ago.
Security forces killed the two militants in an early morning raid in Hebron, a city in the occupied West Bank which has long been a focal point of Israeli-Palestinian confrontation.
Israeli Defence Minister Ehud Barak said the operation was "a quick response to the murder of the four Israelis".
He said in a statement that Israel would "continue to act in any place, without compromise and with determination against terror organisations" to maintain calm in the West Bank.
The Islamist Hamas denounced the killings of Nashat al-Karmi and Mamoun al-Natshi as an "execution" and vowed revenge.
A senior Palestinian security official said the dead men were blamed for the deaths of four Israelis, who were gunned down on Aug. 31, hours before on the launch of a new round of U.S.-brokered Middle East peace talks.
The Israelis, two men and two women from the Jewish settlement of Beit Hagai, were shot on a road near Hebron in the most lethal such attack in the West Bank for four years.
Hamas, which seized control of the Gaza Strip from Palestinian President Mahmoud Abbas' Fatah faction in 2007, opposes the peace talks with Israel. It claimed responsibility for the Aug. 31 shootings and promised more attacks.
After losing Gaza, Abbas's authority has been limited to the occupied West Bank where his prime minister, Salam Fayyad, has been expanding the Palestinian Authority's security force.
Fayyad in a statement denounced Friday's Israeli raid and said such actions "undermine the Palestinian Authority and its achievements in maintaining rule of law and security".
Friday's killings came three weeks after another Hamas commander was shot dead by Israeli forces in the West Bank.
Hamas says around 750 of its supporters have been arrested by Fayyad's forces since the attack on the settlers and on Friday it accused the Palestinian Authority of helping Israel track down its commanders.
"The Israeli aggression on Hebron and the execution of fighters was a fruit of the security coordination and negotiation," said Hamas spokesman Sami Abu Zuhri.
He urged leaders meeting at an Arab League summit in Libya to demand an end to the Palestinian-Israeli negotiations.
The nascent peace talks have been on hold since Sept 26, when Israel refused to extend a 10-month halt to Jewish settlement construction in the West Bank.
Abbas is expected to tell the Arab League that direct negotiations should not continue unless the freeze is renewed.