But members of Hezbollah, the Shiite group at the heart of the Lebanese opposition, gave a more cautious response to the plan, which says a national unity government should be formed in such a way that no one party can impose or block any decision.

Lebanon has not had a president since Nov. 23, initially because of disagreements over who should hold the post, and more recently over the details of a new national unity cabinet.

The plan, approved by Arab foreign ministers meeting at the Arab League in Cairo, endorses the choice of the army chief, Gen. Michel Suleiman, as the next president of Lebanon and provides that he be the arbiter in any contested decisions.

The leader of the Lebanese parliamentary majority, Saad al-Hariri, welcomed the plan. “The declaration by the Arab foreign ministers presents the Lebanese with a new chance to elect a consensus president and fill the presidency,” he said in a statement.

He said that the Lebanese should “treat the results of the Cairo meeting as an achievement.”

But a Hezbollah member of Parliament, Hussein Haj Hassan, told Al Manar, the Hezbollah television station, that the opposition wanted clarifications on some aspects of the next government.

Muhammad Raad, the leader of Hezbollah’s parliamentary bloc, said the movement would wait to see what happened next. “We don’t want to be pessimistic or block the route to any productive decision, especially in a complicated matter like the Lebanese issue,” he added.

The Syrian foreign minister, Walid al-Moallem, told reporters that a solution in Lebanon was up to the Lebanese. “I hope that our Lebanese brothers will think hard before reacting while they wait for the secretary general of the Arab League to arrive to hear from him the Arab point of view,” he added.

But Arab diplomatic sources said Syria, the main foreign power behind the Lebanese opposition, had agreed to the plan, even if it did not overtly give the opposition veto power.

Mr. Moallem said the United States was obstructing consensus in Lebanon, through words and deeds. He did not elaborate.

The draft does not attack Syria, and it enhances the role of General Suleiman, widely seen as sympathetic to Syrian interests.

Lebanese officials said the Arab League secretary general, Amr Moussa, would visit their capital, Beirut, this week to push through a deal.