In a Friday telephone conversation with Mr Yasser Arafat, the head of Israel's Shin Bet secret service, Mr Avi Dichter, reportedly issued an ultimatum: either Mr Arafat ordered his security agencies within 24 hours to start arresting dozens of alleged violent Palestinian militants on a list of names compiled by Israel, or Israel would take action.
The 24-hour deadline having expired, Mr Dichter apparently made good on his threat yesterday: Osama Jawabreh (30), leader of a militant faction of Mr Arafat's Fatah movement, went to make a phone call at his favoured telephone booth in the heart of Nablus and was blown to smithereens. Two Palestinian children nearby were also hurt.
Although Israel declined to comment on the killing, a pilotless drone was reported to be flying overhead at the time of the blast.
Last week, the Israeli cabinet authorised the army to resume the policy of assassinations of alleged bombing orchestrators. Israeli officials claimed Mr Jawabreh had been involved in at least six bombings and attempted bombings, and that he ran a bomb-making factory used by Hamas and Fatah.
Marwan Barghouti, a Fatah leader in the West Bank, warned: "With this assassination, Israel's Prime Minister Ariel Sharon has opened the gates of hell for the Israelis."
The killing brought to eight the number of Palestinians to have died in Intifada violence in the 11 days since a cease-fire supposedly came into effect. Six Israelis have been killed in the same period.
On Friday night, Mr Arafat had assured a group of Israeli journalists that he was doing his utmost to make the cease-fire work.
Mr Arafat is urging the Americans to capitalise on the cease-fire by brokering a speedy resumption of peace talks. But Mr Sharon, who is heading to Washington for talks with President Bush tomorrow, said yesterday that there could no talks until a complete halt to violence was maintained for 10 days, and that this period would have to be followed by six more weeks of "cooling off".
Mr Sharon also told a Newsweek interviewer that Mr Arafat was an "obstacle" to peace, and that, "If he were not here, it would be easier."
En route to Washington, Mr Sharon met yesterday with British Prime Minister Mr Tony Blair who, according to Israel TV, told him that if 20 British civilians were blown up in central London, he would respond forcefully.
Mr Blair was alluding to the killings of 21 Israelis by a suicide bomber in Tel Aviv on June 1st - a blast to which Mr Sharon chose not to respond with military strikes against Palestinian targets.