At least 13 people have died after a suicide bomber attacked a packed Jerusalem pizza restaurant.

Six children are among the dead and more than 70 other people have been injured.

Ten of the injured are thought to be in a critical condition.

Israel Radio says the extremist Palestinian group Islamic Jihad has claimed responsibility for the attack.

A second device - a pipe bomb filled with nails - had been placed outside the restaurant but did not detonate, reports said.

Police said initial indications are that a bomber detonated his explosives inside the Sbarro restaurant, in the heart of the city.

The restaurant and the streets were full of people on their lunch break at the time of the blast.

Bodies were left lying in the restaurant window after the blast. The inside was gutted, with shards of glass and debris littering the streets outside.

Chairs from the restaurant were strewn on the pavement and people were crying and huddled on the street.

"The working assumption from initial findings on the scene is that it was a suicide bomber," said Ilan Franco, the deputy police commander in Jerusalem. He said the bomb was packed with nails, intended to make it more deadly.

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