Israel has killed a senior leader of the Islamic Jihad militant group in a weekend that has seen the region’s worst outbreak of violence since Israeli troops withdew from Gaza.The missile strike on Mohammad al-Sheikh Khalil’s car was part of Israel’s response to mulitiple rocket attacks by Palestinian militants on its territory. Khalil’s deputy was also killed. Islamic Jihad has threatened to abandon its ceasefire. But the Hamas group has said it will not launch any further attacks. “We are committed to the Cairo agreement. We are calling our militant groups to stop their activities against Israeli occupation outside Gaza Strip,” one of its leaders said. The announcement came hours after the Israeli cabinet said its army would resume the targeting the leaders of guerrilla organisations. Helicopter strikes killed two militants on Saturday wounded 20 other Palestinians. In a parallel move Israeli forces arrested around two hundred Palestinians in the West Bank and mobilised troops along the border with Gaza. The escalation was sparked by an explosion which killed 16 people at a Hamas rally. Militants fired dozens of rockets at Israel which it blamed for the blast. But the Palestinian Authority said it was caused by the accidental detonation of Hamas’s own explosives.