BEIRUT, Lebanon — Heavy fighting broke out Monday between government supporters and opponents in Lebanon's second-largest city, where the two sides battled with rocket-propelled grenades, heavy machine guns and mortars, security officials and residents said.

Residents said they heard strong explosions reverberating through Tripoli. At least six people were wounded, security officials said.

The fighting had stopped Sunday morning after Lebanese troops deployed between the two sides, then flared again Monday after soldiers pulled back when the situation calmed.

The fresh clashes erupted when pro-government forces thought opponents gathering for a funeral in a nearby neighborhood were preparing a new attack, the security officials said on condition of anonymity because they were not authorized to talk to the press.

Near Beirut, paramedics said at least 16 people were killed in fighting Sunday in the mountains overlooking the capital. More than 20 people were wounded, they said, also on condition of anonymity because they were not authorized to talk to the press.

The fighting in the town of Chouweifat calmed late Sunday after Druse leader Walid Jumblatt called on his Druse opponents, who are allied with Hezbollah, to mediate a cease-fire and hand over the region to Lebanese troops.

Iran's state-run Press TV reported on its Web site that 17 opposition fighters were killed in the mountain clashes. It did not elaborate, and the Iranian-backed Hezbollah militia refused to comment.

Officials could not immediately provide casualty figures from other mountain towns where fighting also raged a day earlier. But the latest deaths pushed to 54 the number of people killed since violence erupted Wednesday, in the worst internal clashes since the end of the 1975-90 civil war.

The unrest began last week when Lebanon's government decided to sack the chief of airport security for alleged ties to Hezbollah, and also declared the militant group's private telephone network illegal. Hezbollah leader Sheik Hassan Nasrallah said the decisions amounted to a declaration of war.

Arab foreign ministers met in Egypt on Sunday and pledged to send a delegation to Beirut to help find a solution. The delegation was expected in Beirut on Tuesday.

The Hezbollah-led opposition issued a statement welcoming the planned visit.

Meanwhile, shops began opening in the capital and more civilians were seen emerging from their homes, though traffic was lighter than usual. Many schools and universities were still closed.

A minor clash broke out at dawn between government supporters and Hezbollah-allied pro-Syrian gunmen in the busy Hamra district, security officials said on condition of anonymity, also because they were not authorized to speak to the media. Two cameramen for Al-Jazeera television, who arrived at the scene to cover the shooting, were lightly wounded and briefly hospitalized, the channel said.

Most gunmen have withdrawn from Beirut's streets, but those from the Hezbollah-allied Syrian Social Nationalist Party remain posted outside the party's offices in the Hamra and Rawche areas. Hamra is adjacent to the residence of top Sunni pro-government leader Saad Hariri, which is ringed by army commandos.

After the civil war ended in 1990, all of Lebanon's various militias surrendered their weapons and transformed into political parties, keeping only small arms. Only Hezbollah was allowed to keep its arms because it was considered a resistance movement battling Israel.

But over the years, the groups have accumulated more weapons and reasserted control in different areas.

Major roads in Beirut, including the main airport highway, were still blocked Monday with huge sand barriers. The road closures are part of what the Hezbollah-led opposition has called a "civil disobedience" campaign, which it has vowed to continue until the government reconsiders the two decisions that sparked the violence.

The Hezbollah-led opposition quit the Cabinet 18 months ago, demanding larger representation that would give them veto power over government decisions. The deadlock has kept parliament from electing a new president since November.

Army commander Gen. Michel Suleiman is the consensus candidate for president and the army's success in calming Beirut over the weekend could enhance his chances of being elected.

But Hezbollah's show of force in Beirut served a blow to Washington. The U.S. has long considered Hezbollah a terrorist group and condemned its ties to Syria and Iran. The Bush administration has been a strong supporter of Prime Minister Fuad Saniora's government and its army for the last three years.