Israel's internal security service says it has arrested six Palestinians from the West Bank suspected of preparing explosives and planning the bomb attack on a bus in Jerusalem that wounded 21 Israelis last month.

The Shin Bet said Sunday that the suspected militant cell from the Bethlehem area was planning other car bombings and shooting attacks.

It says one of the detained suspects, Mohammad Sami Abed al-Hamid al-Azza, from the Aida refugee camp in Bethlehem, learned how to build explosives from online videos.

It says he procured the explosives from others affiliated with the Islamic militant group Hamas and that they recruited and trained the bomber, Abed al-Hamid Abu Sarour, who died from his wounds in the April 18 explosion.