A Palestinian suicide bomber has detonated explosives near a group of Israeli border police, killing himself but causing no other casualties.

Israeli border police say they spotted a "suspicious" Palestinian man approaching their vehicle near the West Bank city of Tulkarm. Police say when border guards ordered the man to stop, he set off the explosives, killing himself and damaging the police patrol vehicle, but causing no other injuries.

Israeli Defense Minister Binyamin Ben-Eliezer said the man was one of five suicide bombers currently being sought by security forces.

The bombing came one day after Israel began building a controversial security fence aimed at stopping Palestinian militants from crossing into the Jewish state and launching attacks. Palestinians say the new barrier will increase tensions after more than 20 months of violence.

The first section of the fence will run about 110 kilometers from a point northeast of Tel Aviv to south of the port city of Haifa, running roughly parallel to the Mediterranean Sea. For much of the distance the fence will run along the currently unmarked frontier, known as the Green Line, that divides Israel and the West Bank. The electronic fence is designed to separate the Palestinian-ruled areas of Jenin, Tulkarm and Qalqilya from nearby Israeli cities.

Some Israeli right-wing leaders oppose construction of the fence, saying it will establish boundaries that will be difficult to change during peace negotiations. They say such a barrier will weaken their claims to land in the West Bank, which they believe are a biblical birthright for the Jewish people.

The fence is expected to take about one year to build and will cost about $1 million a kilometer.

Meanwhile, Israeli Prime Minister Ariel Sharon has rejected the idea of a provisional Palestinian state. Mr. Sharon told his cabinet Sunday that such a development is not possible until the Palestinian Authority carries out major reforms.

The White House has acknowledged that an interim Palestinian state is among the ideas being considered as President Bush prepares to give his views on a possible path to peace in the Middle East. U.S. officials say the president may reveal his proposals as early as this week.