The IDF was conducting sweeping arrests of wanted Palestinian men in the West Bank early Sunday, military sources said.
The military said the arrests were still underway, and would not specify how many wanted men were taken into custody. Israel Radio said more than 80 members of Hamas and Islamic Jihad movements had been detained.
The arrests were being carried out as Israel embarked on an offensive against Hamas activists in the Gaza Strip who bombarded Israeli towns with rockets.
The offensive crushed hopes that Israel's recently completed Gaza pullout would jumpstart peace talks, and intensified pressure on Palestinian leader Mahmoud Abbas to confront insurgents.