Israeli officials ratcheted up their tough talk on Sunday after an airstrike killed four Palestinian militants in Hamas-run Gaza, but both sides left the door open to restoring a truce that has broken down.

Prime Minister Ehud Olmert of Israel laid responsibility for a recent increase in violence with Hamas and other militant groups active in Gaza. Mr. Olmert was speaking at the start of the weekly cabinet meeting shortly after the four militants were killed in northern Gaza. The men, members of the small Popular Resistance Committees, were planning to fire rockets or mortar shells at Israel, according to the group and the Israeli military.

At least 15 militants, many of them from Hamas, have been killed in Gaza in almost two weeks of clashes with Israel. Israeli officials say that about 20 rockets and mortar shells were fired from Gaza over the weekend, including at least two imported Katyusha-type rockets fired by Hamas at the Israeli coastal city of Ashkelon. Israel’s transportation minister, Shaul Mofaz, a former defense minister and army chief of staff, told the Israeli news Web site Ynet that Israel should “stop talking and launch a personal targeted killing policy” against Hamas, the militant Islamic group that took over Gaza in 2007.

But Mr. Olmert said that his government had always acted in such situations with “equanimity and sagacity” and would continue to do so now.

The defense minister, Ehud Barak, who is said not to favor a large-scale military operation in Gaza at this time, said that no one should regret any month that passes quietly. “Hotheadedness is not a replacement for policy,” he said.

In Gaza, Hamas leaders continued to express interest in a renewal of the Egyptian-brokered truce that took effect in June. Mahmoud Zahar, a senior Hamas official, said that Arab parties were also “emphasizing the commitment of Israel” to the truce, suggesting that Hamas had received messages to that effect.

To a large extent, the truce is dependent on Hamas being able and willing to rein in smaller groups like the Popular Resistance Committees. Mr. Zahar said Sunday that “other factions” would persuade them to stay in line.

The calm started to unravel almost two weeks ago when an Israeli force entered Gaza for the first time in five months to destroy a tunnel Israel feared Hamas might use to abduct soldiers in a cross-border raid.