Palestinians accused Israel of trying to blow up an activist of President Yasser Arafat's Fatah movement and undermine US efforts to ease violence sweeping the West Bank and Gaza Strip.
Palestinian officials said a booby-trapped car was discovered yesterday and taken to a field near Preventive Security agency headquarters in the West Bank city of Ramallah, where it exploded as an Israeli helicopter hovered overhead.
Mr Yasser Abed Rabbo, the Palestinian information minister, identified the alleged assassination target as Mr Nasser Abu Hmeid. Mr Rabbo said two Palestinian "collaborators" with Israel had been arrested and admitted their involvement.
Asked to comment, the Israeli army said: "We are unaware of any such explosion." Palestinian television showed the charred remains of what it said was Mr Abu Hmeid's car.
It was the second time a US arranged meeting between Israeli and Palestinian security chiefs has been swiftly followed by a heated incident certain to keep tensions at boiling point.
After a security meeting a week ago, Israeli soldiers shot at cars carrying the Palestinian delegation home to Gaza, wounding two bodyguards. Israel said the soldiers had shot after coming under fire.
Israel has said it does not pursue a deliberate policy of assassination but does target Palestinians who plan or carry out attacks against its citizens and soldiers.
In a further indication that security meetings have failed to stem the bloodshed, a 14-yearold Palestinian youth was shot dead during an exchange of fire between Israeli soldiers and Palestinian gunmen, witnesses and hospital officials said.
Earlier in the day, Palestinian officials said Israeli soldiers killed one Palestinian and wounded another when they fired on the pair near the Israeli military junction of Kissufim in the Gaza Strip. An Israeli soldier was wounded by automatic gunfire along a road near the Palestinian West Bank village of Beit Jala.
Palestinian security officials in Ramallah said the two men taken into custody had sold the explosives-laden car to Hmeid, but that he grew suspicious and alerted authorities.
Palestinian officials have accused Israel of assassinating more than 20 activists since the Palestinian uprising against Israeli occupation began in September.
Israeli Public Security Minister Mr Uzi Landau, speaking before news of the alleged assassination attempt, told Israeli television that Prime Minister Mr Ariel Sharon had to keep the pressure on Mr Arafat to crack down on violence.
In a sign of growing international concern, Jordan's Foreign Minister Mr Abdulilah al-Khatib met Mr Arafat yesterday, and the US and Russia issued a joint statement calling for an end to violence.
At least 376 Palestinians, 13 Israeli Arabs and 71 other Israelis have been killed in the violence that erupted last September after peace talks deadlocked.