BEIRUT (AFP) - - Hezbollah fighters, their guns blazing, seized control of west Beirut on Friday after three days of street battles with pro-government foes pushed Lebanon dangerously close to all-out civil war.

The sectarian fighting had eased by early afternoon and the army and police moved across areas now in the hands of Iranian-backed Shiite opposition forces who routed Sunni militants loyal to the Western-backed government.

"There are no clashes anymore because no one is standing in the way of the opposition forces," a security official said as convoys of gunmen firing celebratory shots into the air and flashing the victory sign took to the streets.

But as foreigners scrambled to leave the troubled nation, it was unclear what the immediate future would hold, amid fears the protracted political feud could plunge Lebanon back to the dark days of the 1975-1990 civil war.

"All those who believe in democracy and pluralism are under siege in Beirut," said Social Affairs Minister Nayla Moawad.

Terrified residents cowered inside early Friday as the rattle of gunfire and the thump of exploding rocket-propelled grenades rang out across mainly Muslim west Beirut.

Sunni government loyalists fought running battles with Shiite gunmen, routing them from their strongholds and forcing the closure of the media outlets run by the family of parliamentary majority leader Saad Hariri.

At least 11 people have been killed and dozens wounded in three days of fighting that dramatically escalated on Thursday after Hezbollah chief Hassan Nasrallah said a government crackdown on his powerful militant group was a declaration of war.

Christian opposition leader Michel Aoun, a Hezbollah ally, hailed Friday's events in the besieged capital as a "victory for Lebanon."

The unrest triggered urgent international appeals for calm, while Arab nations led by regional powerhouse Saudi Arabia are pushing for a special session of foreign ministers to tackle the crisis.

Lebanon's feud is is widely seen as an extension of the confrontation pitting the United States and its Arab allies and Israel against Syria and Iran, which back Hezbollah -- regarded as a terrorist group by the West.

In Beirut, most shops and businesses remained shuttered while tanks rolled through the streets and hundreds of riot police and troops patrolled the city but with orders not to intervene in the conflict.

In scenes reminiscent of the 2006 war between Israel and Hezbollah , Lebanon was largely cut off from the outside world, with the international airport and Beirut port shut and several key highways blockaded.

But hundreds of people were able to flood to border crossings with Syria to escape the violence and foreign governments began putting in place plans to pull out their nationals.

An airport official said all flights had been cancelled on Friday with the main road from Beirut barricaded by Hezbollah fighters. "As soon as they open the road, the flights will resume."

Hezbollah, the most powerful armed group in Lebanon and a growing political force, was the only Lebanese faction allowed to keep its weapons after the civil war to fight Israel forces occupying the south.

"Hezbollah has used its weapons to carry out a coup. They said their weapons were for the resistance but they've made clear that they are for a coup," said former president Amin Gemayel, a member of the majority, speaking from Paris.

Witnesses recounted the chaos and fear that reigned in Beirut overnight as people rushed to stores that remained open to stock up, while others were trapped in their homes.

"It was a hellish night. The armed militants were everywhere shooting all over the place," said west Beirut resident Rima.

Although west Beirut was virtually under siege, in the predominantly Christian eastern sector of the city, life was going on as usual, with shops and other businesses open.

Israeli President Shimon Peres claimed the violence was fomented by archfoe Iran to further what he said was Tehran's goal to control all of the Middle East.

Syrian President Bashar al-Assad -- whose country is Iran's closest regional ally -- said the unrest was a purely "internal affair" but called for dialogue.

Nasrallah delivered his defiant speech on Thursday after the government launched a probe into a private communications network run by Hezbollah, which critics say has become a "state within a state."

"The decisions are tantamount to a declaration of war and the start of a war... on behalf of the United States and Israel," Nasrallah charged. "The hand that touches the weapons of the resistance will be cut off."

The United States delivered a blunt warning to Hezbollah to stop its "disruptive activities" while UN Security Council members said they were "deeply concerned" over the crisis, a view reflected by other Arab and European leaders.

The crisis will be the focus of talks between President George W. Bush and Lebanese Prime Minister Fuad Siniora in Egypt next week during the US leader's tour of the Middle East.

Regional powerhouse Saudi Arabia, which backs the Siniora government, called for an urgent meeting of Arab foreign ministers, which an Egyptian official said could be held in two days.

The long-running political standoff, which first erupted in November 2006 when six pro-Syrian ministers quit the cabinet, has left the country without a head of state since November, when Damascus protege Emile Lahoud stepped down.