Militant Palestinian group Hamas has vowed revenge for an Israeli helicopter strike that killed one of its senior commanders and three other members in the Gaza Strip yesterday.
Hamas said it could go on fighting Israel forever if necessary and dismissed Palestinian Authority plans to crack down on militants as demanded by Israel and the United States.
"Believe me, any action against us and the Palestinian Authority will find itself face-to-face with the Palestinian people, the masses," Hamas political leader Mr Abdel Aziz al-Rantissi said.
Mr Rantissi said he saw no chance of restoring a cease-fire. "[Israeli Prime Minister Ariel] Sharon made a big mistake. He thought we were weak. No. Believe me, we can go ahead in this conflict forever," he said.
The killing of Ahmed Shtewe (24) and the other members of Hamas's Izz-el-Deen al-Qassam armed wing followed a vow by Israel's army chief Moshe Yaalon to hunt down Islamic militants if Palestinian security forces did not.
The four were killed when helicopter gunships fired missiles at them as they walked near a beach in Gaza City.
Hamas and other militant groups had already vowed to carry out revenge attacks after Israel assassinated a senior Hamas leader in a missile strike in Gaza City on Thursday.
The assassination - in retaliation for Hamas's killing of 21 people in a suicide bombing of a Jerusalem bus on Tuesday in yet another tit-for-tat attack - prompted militant groups to dissolve a seven-week-old truce that underpinned the so-called peace "road map."
Palestinian Information Minister Nabil Amr said the latest Israeli attack undermined the Palestinian Authority's efforts to clamp down on militants on a day on which it closed four arms smuggling tunnels in southern Gaza and issued orders to prevent rockets and mortars from being fired at Israel.
But Israeli officials said the Palestinian Authority's steps were superficial and that it was not cracking down on militants behind suicide bombings and disarming them.