Lebanon's army began taking steps on Tuesday to stop gunmen and groups from illegally carrying arms and to end - by force if necessary - a week of fighting between Hezbollah fighters and pro-government gunmen.

Hezbollah, the Shi'ite Muslim movement backed by Iran and Syria, and its opposition allies have routed supporters of the Sunni-led government in Beirut and hills to the east, in fighting that has pushed Lebanon to the brink of a new civil war.

The Lebanese army has until now stayed neutral in the conflict, which has killed 81 people and raised Arab and international concern over the future of the country.

The fighting erupted on May 7 after Prime Minister Fouad Siniora's government outlawed Hezbollah's communications network and sacked the Beirut airport security chief, who is close to the group.

Hezbollah said this was a declaration of war and launched a series of attacks which briefly won it control of large parts of Beirut - which it then handed over to the army.

The army command said in a statement on Monday night it would work to end all armed presence in cities and villages from 6 a.m. (4 a.m. British time) and authorised troops to use force if necessary.

It gave no further details but a security source said the measure included the arrest of any gunmen, the taking over of armed positions and the storming of suspected arms depots.

Gunmen from both sides remained in the streets and clashes have been widely reported in many parts of the country.

Even if successful, the army's plan did not mean an end to the opposition's civil campaign to force the government to scrap its the sacking of the security chief and dismantling of the Hezbollah communications network.

Much of Beirut remains paralysed by street barricades erected by Hezbollah and its allies. The capital's air and sea ports remain closed.

BLOW TO RULING COALITION

Hezbollah's success has dealt a blow to the Sunni-led ruling coalition and its main patron, the United States, which has cast the country as a fragile democracy endangered by the ambitions of Hezbollah and its Iranian and Syrian backers.

U.S. President George W. Bush said on Monday he would consult regional allies during his forthcoming visit to the Middle East on ways to bolster Lebanon.

"It is critical that the international community come together to assist the Lebanese people in their hour of need," Bush said in a statement. He will travel to Israel, Saudi Arabia and Egypt, starting on Wednesday, and plans to meet Siniora in Egypt on Sunday.

He said the United States would continue to aid the Lebanese military so it can defend the government.

In New York, U.N. Secretary-General Ban Ki-moon, the United States and key European and Middle Eastern nations condemned the violence in Lebanon and urged all parties to end the fighting.

"We remain deeply concerned by the situation in Lebanon, which threatens the stability of the country and the region," the "Friends of Lebanon" said in a statement.

"We call for the immediate cessation of fighting, the withdrawal of gunmen from the streets, the unblocking of roads and the reopening of Beirut International Airport."

Western and Saudi support has so far done nothing to deter Hezbollah from exposing the military weakness of its foes, such as Sunni leader Saad al-Hariri and Druze chief Walid Jumblatt, whose mountain fiefdom was attacked on Sunday.

On the political front, the government has for 18 months resisted opposition demands for veto rights in cabinet, though Hezbollah has now shown it has the military muscle to veto decisions it dislikes.

The turmoil has paralysed state institutions and left Lebanon without a president since November. The election of a president by parliament was postponed to June 10 from Tuesday, the 19th delay caused by the crisis.

An Arab League mission will arrive in Beirut on Wednesday to mediate between the rival leaders.