Senior Israeli officials say the military will respond more aggressively to Palestinian attacks and warn the current flare-up in violence could delay Israel's plans to pull out of the Gaza Strip and parts of the West Bank this August. The warnings follow an unusually heavy barrage of rocket and mortar attacks by Palestinian militants and the deaths of two members of Hamas.

Israeli Defense Minister Shaul Mofaz has ordered the military to respond more vigorously and use all necessary means to halt attacks by Palestinian militants in Gaza.

The decision was made during a meeting of military and security chiefs.

Deputy Defense Minister Zeev Boim also sent a message to the militants - stop the attacks or risk collapse of the cease-fire, which has lasted for more than three months, despite some violations.

The deputy minister told Israel Radio that if the militant attacks continue the security forces will respond more forcefully. He said Israel wants calm before its planned disengagement from Gaza and he warned there will be no Israeli withdrawal under fire.

The warnings follow a flare-up in violence during the past two days.

Early Wednesday, a Hamas militant was killed, apparently while preparing to plant a bomb along the heavily patrolled Gaza border with Egypt. Later, Palestinian militants launched dozens of mortar shells and crude Qassam rockets at Israeli targets, mostly settlements inside Gaza.

Israel launched a helicopter missile strike against what military officials said was a group of Hamas militants firing more rockets. One militant later died from wounds sustained in the attack.

Tawfik Abu Khufa, spokesman for the Palestinian Interior Ministry, blamed Israel for trying to stir up trouble.  He said the Israeli helicopter missile attack meant that Israel had already reverted to its practice of targeted assassinations. He accused Israel of trying to provoke violence.

Some Palestinian officials are expressing frustration with the militant groups for not sticking to the cease-fire they agreed to, but many also blame Israel for not doing enough to ease conditions for Palestinians.

Israeli officials say the Palestinian Authority has not done enough to crack down on the militants. Some say the current upsurge in violence is also a sign of Hamas flexing its muscle after doing well in recent local council elections.

Despite the latest violence, senior officials from both sides have met to try to prevent further escalation.