A bomb in a backpack or baby carriage detonated on a bus near the Jerusalem Bus Station Wednesday afternoon, killing one and wounding more than 30 on board and pedestrians nearby, Israeli police said.

The one-to-two kilogram bomb which exploded at about 3 p.m. local time (1300 GMT) is the first bombing attack in Jerusalem during the past four years, a police spokesman told Xinhua.

One was killed and several others were in critical and moderate condition. Emergency medical crews evacuated all casualties to local hospitals within minutes.

An 18-year-old girl who was on a bus about 200 meters away from the blast said she felt the pressure wave when the bomb exploded. "Everyone on the bus jumped, and then the driver stopped the bus," she said.

"Everyone started to call people on their cell phones, and the driver kept driving a short distance and then opened the doors for people to get off," she added.

Medics from Magan David Adom emergency services have started to clear the site.

Police and security officials are searching for other bombs. Jerusalem Police chief Aharon Franco said that police are also searching for the assailants who placed the bomb.

"I don't think that Jerusalem was specifically targeted," Jerusalem Mayor Nir Barak, who arrived at the scene, told TV Channel 2. He said the attack is due to "the general deterioration in security" in Israel and recent escalation along the border with the Gaza strip."