Monday started as a normal day for Israeli bus driver Haim Avraham, as he drove along his usual route from the northern city of Kiryat Shmona to Tel Aviv.

But when he stopped his vehicle at Karkour junction just outside the town of Pardes Hanna, his bus - packed with passengers - was ripped apart by the force of a huge explosion.

We didn't manage to get inside to save anyone. It was pretty difficult watching people we couldn't help any more

Michael Yitzhaki, survivor

"A car exploded alongside us and the whole bus was thrown in the air," Mr Avraham said from his hospital bed.

In a tactic rarely applied during the two-year-old Palestinian uprising, the attacker's jeep pulled up behind the bus as it was picking up passengers, and set off the explosives.

"I was 60 metres from the bus station... and I heard an explosion. The bus was completely shattered," a witness told Israel army radio.

"It was completely wrecked," he said.

Blazing inferno

Eyewitnesses said the blast sent a huge black mushroom cloud into the sky - turning the bus into a blazing inferno.

"The explosion was so strong that I fell to the floor," one passenger said. "I looked back and quickly got off the bus, then it burst into flames."

A few passengers managed to escape, some by crawling from the windows. But many others were not so lucky - and were left trapped inside the blazing vehicle.

For the those who escaped, the first priority was to phone home

"The flames ate up the bus with amazing speed," said Michael Yitzhaki, one of those who escaped.

"We didn't manage to get inside to save anyone. It was pretty difficult watching people we couldn't help any more."

The flames were so hot that some of the ammunition carried by soldiers riding on the bus blew up, creating a chain of further explosions.

"The bus burst into flames - apparently the gas tank ignited - but what was even worse was that the soldiers' ammunition began to explode and the whole bus was completely engulfed in flames," said Mr Yitzhaki.

When the fire was eventually extinguished, an hour after the blast, both the bus and the car were blackened beyond recognition.

Eyewitness Meital Ziskin summed up the scene when he said: "It was like an earthquake. The whole bus is burnt and nothing is left of it."