BEIRUT, Lebanon - The Lebanese army imposed a curfew on the capital yesterday after hundreds of government supporters and foes wielded rocks, Molotov cocktails, and sometimes guns in street battles that dragged past nightfall. Four people were killed and 150 wounded, officials said, many of them soldiers who at times stood helplessly between the two sides.

The clashes, which began with an altercation in a university cafeteria and spread to the surrounding neighborhood of Tariq Jedideh, offered a bitter contrast to the optimism of an international conference in Paris, where more than $7.6 billion was pledged to help Lebanon's economy recover from last summer's war with Israel.

As the grants and loans were announced, bursts of gunfire echoed along the airport road and columns of black smoke rose from burning cars, in some of the worst clashes since Lebanon's 15-year civil war ended in 1990.

Hundreds of followers of the Shiite Muslim movement Hezbollah poured into the neighborhood in red and blue helmets, many of them carrying sticks and chains. At one point, their opponents burned a Hezbollah banner, a searing image that spoke to the jarring rise in tension between Sunni Muslims, largely aligned with the government, and Hezbollah's supporters since the crisis began two months ago.

The army and security forces deployed in force after the clashes erupted, but often fired into the air or simply gave way. For hours, crowds surged at one another, then retreated, usually separated by soldiers crouched behind armored personnel carriers. More clashes ensued elsewhere, as Sunni Muslim crowds firebombed the headquarters of a party allied to Hezbollah, and Shiite youths rampaged along a downtown street lined with bank headquarters.

The images reverberated across Beirut, anxious and uneasy since Dec. 1, when Hezbollah and its allies began their campaign to topple the government of Prime Minister Fuad Saniora with a mass protest in the downtown area.

In the streets, there were grim reminders of the civil war: Young, swaggering men asked residents whether they were Sunni or Shiite, cars were attacked because of their owner's sect, and both sides questioned whether the army could protect them.

"It's going to get worse. Look at all this," said Salah al-Sheikh, 40, a Sunni resident, waving his hand across a devastated block of incinerated or smashed vehicles, the street littered with rocks, sticks and shattered glass. "A few days ago, they were in the same schools and the same universities. Look what's happening now. Why? That's all I want to ask. Why?"

Behind him, another Sunni resident shouted: "Give us weapons! Give us weapons!"

The fighting was an episode, writ small, of an increasingly precarious Middle East, riven by growing sectarian tension, simmering civil conflict here and in the Palestinian territories, and a deepening war in Iraq. Leaders across the political divide called on their supporters to exercise restraint. Lebanese officials said the army insisted that all sides agree to a curfew before it declared its start at 8:30 p.m.

"I call on everyone to return to the voice of reason," Saniora said from Paris, where he attended the aid conference.

Sheikh Hassan Nasrallah, Hezbollah's leader, issued a religious edict to his followers to withdraw. "This is an order on everyone," he said.

Nabih Berri, the speaker of parliament, whose Amal movement is allied with Hezbollah, warned that events were spiraling out of control. "We must all be united," he said, "or we have to look for our country in the graveyard of history."

Nations Pledge $7.6 Billion to Lebanon

World powers pledged $7.6 billion

in donations, loans and other assistance yesterday to help Lebanon's fragile Western-backed government.

The global donors met in Paris for

a one-day conference on developing ways to help Lebanon recover from last summer's war between Israel and Hezbollah and address its

$40 billion in debt.

Lebanon experienced promising economic growth during the last decade, as the scars faded from a 15-year civil war. But much of the progress was undone by the summer war, which devastated towns in southern Lebanon, and by weeks of political deadlock that have closed shops and businesses.

Among amounts pledged:

Saudi Arabia, $1.1 billion.

United States, $770 million.

France, $650 million.

European Union, $650 million.

United Arab Emirates,

$300 million.

Britain, $163 million.

Germany, $134 million.

China, $4 million.

Denmark, $3.5 million.

- Associated Press