GAZA CITY, Gaza Strip ? The chief of the Palestinian intelligence service was severely wounded Saturday by a bomb blast that tore through his headquarters in the northern Gaza Strip, killing one of his bodyguards and injuring seven other people.

Hours later, an Israeli airstrike in Gaza targeting a senior Islamic Jihad gunman killed him and three other people, including a 5-year-old child, Palestinian hospital officials said.

The explosion at the intelligence headquarters came at time of rising tension between leaders of Hamas, the radical Islamic group now running the Palestinian government ministries, and Mahmoud Abbas, president of the Palestinian Authority and head of the rival Fatah movement.

Maj. Gen. Tariq Abu Rajab, the intelligence chief, reports directly to Abbas, and Palestinian officials described the bombing as an assassination attempt.