GAZA CITY, Gaza Strip ? The militant Islamic group Hamas vowed revenge Saturday after one of its founding members and three bodyguards were killed in an Israeli helicopter attack. The Israeli army promised to strike the militants again.

Hamas threatened to attack Israeli political leaders and said no Israeli should feel safe after helicopter gunships swooped in and fired missiles at a car carrying Hamas strongman Ibrahim Makadmeh, 51, Saturday.

“Israel has just widened the field of battle and widened the number of possible targets,” said Mahmoud Zahar, a Hamas political leader and spokesman, after identifying Makadmeh’s mangled body.

“We encourage our cells to plan and prepare strikes against the occupiers … especially Jewish political leaders,” the group’s military wing said in a statement.

The last time Israeli forces killed a high-ranking Palestinian political figure was August 2001, when Abu Ali Mustafa of the Popular Front for the Liberation of Palestine was slain. His killing led to the assassination of Israeli Tourism Minister Rehavam Zeevi on Oct. 17, and touched off a series of fierce clashes between Palestinians and Israeli troops in the West Bank.

Makadmeh’s killing came after Hamas claimed responsibility for an attack Friday on a Jewish settlement that left two dead, and a suicide bus bombing Wednesday that killed 16. One of the passengers injured on the bus died Saturday.

A boy holding a Palestinian flag walks in front of armed Hamas militants during the funeral procession of Ibrahim Makadmeh, 50, a prominent Hamas leader killed when Israeli helicopters rocketed his car.

Israel rarely takes responsibility for such killings, but in an unusual statement, Prime Minister Ariel Sharon’s adviser, Shoval, called Saturday’s operation in Gaza a “success.”

Sharon’s new hardline government has promised more attacks against militants, and Saturday the army said it would launch more strikes. It has also promised stepped up strikes against Hamas and its infrastructure and appears to be digging into Gaza, considered a stronghold of Hamas.

Israel seized parts of Gaza in its most significant occupation in 29 months of fighting as embattled leader Yasser Arafat moved closer to sharing power.

The PLO Central Council, meeting in the West Bank town of Ramallah on Saturday, approved Arafat’s request to create the post of Palestinian prime minister and cleared the way for the Palestinian legislature to define the job’s powers.

“I want the international community to know that the Israeli occupation is the biggest obstacle standing in front of our reform process,” Arafat said Saturday.