There was no immediate claim of responsibility. The explosion coincided with a German-brokered prisoner swap between Israel and the Lebanese guerrilla group Hezbollah, although it was not clear if the two were connected.
The blast went off just 100 yards from Prime Minister Ariel Sharon’s official residence in the Rehavia district in downtown Jerusalem. Sharon’s whereabouts were not immediately clear.
Reporters saw two bodies on the bus and three lying on the ground. Paramedics said 30 people were wounded, several of them seriously.