JERUSALEM — Israel’s defense minister, Amir Peretz, yesterday endorsed the deployment of an international force, possibly led by NATO, in southern Lebanon.

Israel had previously dismissed the proposal, first put forward by Prime Minister Blair, as premature. But with the Israeli military finding it hard to impose any crushing victory on the Hezbollah militia, the government has begun to think about longer-term ways of protecting its northern border.

“Israel sees the possibility of deploying a multinational force [in Lebanon] with a strong mandate. The force would possibly be a NATO force,” Mr. Peretz said after meeting German Foreign Minister Frank-Walter Steinmeier.

However, there was widespread skepticism about the international community’s ability to deploy what Mr. Blair called a “robust” force to the volatile area. The 2,000-strong U.N. observer mission that has been monitoring the volatile border for 28 years has proved inadequate to the task.

The Washington Post yesterday quoted American officials as saying America could not contribute to a force because it was already stretched by operations in Iraq and Afghanistan.

The officials said the force could be of between 10,000 and 20,000 men and be led by a French or Turkish contingent. Italy, Brazil, Pakistan, India, and Germany also have been named as nations that could send military units.

“We are talking about a force that has to be acceptable to both Israel and Lebanon and that will be targeted by Hezbollah,” the director of studies at the Institute of Policy and Strategy at Israel’s Herzliya Interdisciplinary Center, Shmuel Bar, said. “Which country will accept to put their soldiers in that position?” An Israeli minister, meanwhile, expressed disappointment at the results of the military offensive so far, saying it was an illusion to think Hezbollah could be completely wiped out as an armed force.

The minister without portfolio, Eitan Cabel, said, “I admit I had hoped for better from the army.”

He is the first minister to express reservations on the success of the offensive, which opinion polls show is generally popular among Israelis. Mr. Cabel added, “I continue, however, to think that the army will be able to provide the political authorities with the means to engage in negotiation from a position of strength.”

The Israeli chief of staff, Lieutenant General Dan Halutz, sought to lower expectations of total extinction of the Hezbollah guerrillas.

The army, he said, could not bring the rocket fire to a complete stop. “There will always be some terrorist to fire a missile. But I believe we’ll be able to push them north and reduce the accuracy of their fire. The other side must reach the conclusion that the price it pays for continuing the fire is intolerable.”

The military strategy, he said, was based on Israel’s need to “restore military deterrence against terrorist organizations,” such as Hamas or Hezbollah, after what he said had been a period of Israel giving the impression that it had softened toward its enemies.