Updated

Israeli tanks rolled into this West Bank town Wednesday, Palestinian security officials said, just hours after an Islamic militant from the area blew himself up next to a crowded Israeli bus, killing at least 16 passengers and wounding 38.

Palestinian security officials said two dozen armored vehicles drove into Jenin from three directions. Two attack helicopters fired machine guns toward one neighborhood, witnesses said. There were no immediate reports of injuries.

In expectation of an Israeli incursion, Jenin residents quickly left public areas and sought shelter in their homes.

Jenin, a militant stronghold, has been the target of repeated Israeli raids in recent months, including a brief incursion Monday. During Israel's six-week military offensive against Palestinian militias, which ended last month, the Jenin refugee camp adjacent to the town was the scene of the fiercest fighting.

Wednesday's bombing was carried out by the Islamic Jihad group. Members of Islamic Jihad's military wing said the assailant was from the Jenin area, but would not give his name for fear of Israeli reprisals against his family.