An explosion has ripped through a bus in northern Israel, killing at least 15 people and injuring more than 30 others in what police say was a suicide bomb attack.

I saw the bus go up in flames. It was completely wrecked

Eyewitness

Israeli police spokesman Haim Boniemonsky said the attacker was among the dead.

The blast took place during the afternoon rush hour, near the West Bank.

The Israeli Government has blamed Yasser Arafat's Palestinian Authority for the attack, but Mr Arafat has condemned the bombing.

The Palestinian militant group Islamic Jihad has claimed responsibility for the attack, claiming it was a "martyrdom operation" or suicide bombing.

BBC Jerusalem correspondent James Reynolds says this is the worst attack against an Israeli target for several months - and it is likely to prompt a response from the Israeli Government.

'Terrified'

Police say the bus, which was travelling between Kiryat Shmona to Tel Aviv, burst into flames at a junction just outside the town of Pardes Hanna, after a jeep packed with explosives pulled up next to it.

The jeep exploded, destroying the back of the bus and trapping many passengers - some of whom were soldiers - inside.

Some witnesses described a cloud of black smoke rising from the scene of the blast.

"I was 60 metres from the bus station... and I heard an explosion. The bus was completely shattered. I saw the bus go up in flames. It was completely wrecked," one witness told Israel Radio.

Michael Yitzhaki, who escaped from the bus, said: "The flames ate up the bus with amazing speed...We didn't manage to get inside to save anyone. It was pretty difficult watching people who we couldn't help anymore.

"What was even worse was that the soldiers' ammunition began to explode and the whole bus was completely engulfed in flames."

Authority blamed

David Baker, an official in Prime Minister Ariel Sharon's office, responded to the attack by saying: "Palestinian terrorists are waging war in Israel's streets, cafes and on our roads,"

We reject such attacks against civilians

Yasser Arafat

"The Palestinian Authority has become a prime authority on terror and could not care less about preventing it."

Mr Arafat said: "The decision of the Palestinian leadership is that it is opposed to attacks against Palestinian and Israeli civilians. We reject such attacks against civilians."

The explosion is the first fatal attack on an Israeli target since a suicide bomb blast on 10 October which killed the bomber and one woman.

US diplomacy

The United States has condemned the latest attack.

"The administration condemns the most recent attack in Israel. It's another reminder of how it's so important for peace to be pursued and for terror to be stopped," White House spokesman Ari Fleischer said.

The bombing is a setback for the latest mission of the US envoy William Burns, who is due in Israel on Wednesday for talks with both Israeli and Palestinian officials.

He is due to present a "road map" designed to lead in three stages from a cessation of violence to the creation of a Palestinian state.

Our correspondent says Americans hope that progress would help them win Arab support for a possible war on Iraq.