Israel continued targeting Hamas leaders in helicopter strikes Friday as the military tried to squelch the source of terrorist attacks against the nation.

In the sixth attack in four days, Israeli helicopter gunships fired three missiles at a car in Gaza City (search) Friday night, killing a Hamas (search) militant riding inside.

Video: Israeli Strike Kills Hamas Militant

Hours later, Israel carried out a seventh attack as helicopters fired missiles at a weapons factory, the Israeli military said. There was no immediate word of casualties.

Palestinian sources told Fox News that Fuad Lidawi, a member of the military wing of Hamas, was killed in the sixth attack on the car. The sources said Lidawi's lifeless body arrived at a local hospital soon after the attack.

Doctors said 32 others were wounded, including 10 children.

The Israeli military said the car Lidawi was traveling in had launched homemade rockets at Israel earlier in the day.

Responding to the violence that has killed 36 Palestinians and 24 Israelis since last week, Secretary of State Colin Powell urged all sides to exercise restraint.

"I think we all are anxious to see restraint," Powell said Friday outside the State Department. "And we understand that it's important to get the terror down. And if the terror goes down, then the response to terror will no longer be required."

Concerned over the escalating violence, U.N. Secretary-General Kofi Annan (search) said in an interview published Friday that deploying armed peacekeepers — an idea opposed by Israel — may be the only way to keep the warring parties apart long enough to begin implementing the so-called "road map" to peace and Palestinian statehood by 2005.

The plan envisions an increased role for international monitors, but does not call for armed peacekeepers.

A first contingent of 10 to 15 U.S. monitors, including CIA and State Department officials, was to arrive in the region Saturday, headed by Assistant Secretary of State John Wolf.

Israel TV reported that Dov Weisglass, a senior aide to Israeli Prime Minister Ariel Sharon (search), was flying to Washington for talks with National Security Adviser Condoleezza Rice.

Palestinian Prime Minister Mahmoud Abbas (search) has said he won't use force against the Islamic militant group Hamas and other militants and needs time to persuade them to lay down arms. Egypt is mediating, and talks might be held next week between militant leaders and Egypt's intelligence chief, Palestinian officials said.

Hamas broke off truce talks with Abbas last week, prompting Israel to activate a contingency plan for hunting down Hamas leaders, including the group's founder, Sheik Ahmed Yassin (search), an Israeli security official said, speaking on condition of anonymity.

After Hamas rejection of a cease-fire, however, the group's leaders were marked for death, said the Israeli security official. They are considered "ticking bombs" — and therefore legitimate targets — because they set policy and order attacks on Israelis, the official said.

"There is no immunity for anybody who either orders or executes terrorist activities," said Avi Pazner, a government spokesman.

Military correspondent Alex Fishman wrote in the Yediot Ahronot (search) daily Friday that  "from now on, everyone is in the crosshairs all the time," including Yassin.

In a first such strike, Israel tried this week to kill Abdel Aziz Rantisi (search), a Hamas co-founder and spokesman. Rantisi escaped a missile strike with minor injuries, but in response, a Hamas bomber blew himself up on a Jerusalem bus a day later, killing 17 people.

Israel has targeted members of the Hamas military wing in seven rocket attacks this week, the latest on Friday.

Though the government insists such attacks are the only way to stamp out the militants, an Israeli opinion poll suggested the new policy is unpopular.

Sixty-seven percent of 501 respondents said Israel should halt targeted killings, at least for a while, to allow Abbas to strengthen his shaky position and act against the militants. The poll published in Yediot had a margin of error of 4.5 percentage points.

The road map requires Abbas to dismantle and disarm militias, but he has said he cannot and will not use force against them for fear of setting off a civil war.

Annan told the Israeli daily Haaretz in an interview published Friday that the impasse can only be broken by armed peacekeepers. "In the interim period, I would like to see an armed peace keeping force act as a buffer between the Israelis and the Palestinians," he said.

Palestinians have long called for such a force. Responding to Annan, Palestinian Cabinet minister Yasser Abed Rabbo said an armed force "is the only realistic solution to get out of this cycle of violence and counter-violence." Abed Rabbo said American involvement would be crucial.

Israel rejected the idea.

"Right now, the only thing that binds Israel and the Palestinian is the road map. In the road map, there is a place for American monitors, nothing else. That is Israel's position," said Raanan Gissin, a Sharon adviser.

Israel opposes placing its security in the hands of a third party, particularly one backed by the United Nations or the European Union, seen by Israel as having a strong anti-Israel bias.

The United Nations belongs to the so-called Quartet of Mideast mediators, along with the United States, Russia and the EU. Senior Quartet members, including U.S. Secretary of State Colin Powell, were to meet in Jordan next week to discuss the road map.

"I think we are all anxious to see restraint and we understand that it is important to get the terror down," Powell told Associated Press Television News on Friday. "The terror goes down, then the response to terror will no longer be required."

Also Friday, Abbas was in Jordan where he underwent successful surgery for cataracts in both eyes. His doctor said Abbas was expected to return home Saturday and return to work.

The Associated Press contributed to this report.