ASSOCIATED PRESS WRITER

MICHELLE FAUL

MOGADISHU, Somalia (AP)—Submachine gunfire crackled across central Mogadishu on Sunday on the eve of a protest that threatens to explode into clan violence.

Somalis said two people were killed and three wounded in an hour-long shootout over a water well.

The gunfight was adjacent to the Kilometer Four traffic circle in the southern stronghold of Gen. Mohamed Farrah Aidid, whose supporters held their regular Sunday rally barely a mile away. It wasn’t clear if those in the shootout were affiliated with Aidid or his opponents.

Aidid’s deputy, Mohamed Nur Aliyo, repeated warnings against a demonstration planned for Monday. Protesters plan to cross the Green Line dividing rival clan leader Ali Mahdi Mohamed’s territory from south Mogadishu.

Tens of thousands of people are expected.

‘‘If they come over, we are not responsible for what will happen,’‘ Aliyo told hundreds of cheering people at the rally. ‘‘They want this to create problems, not support peace.’‘

Ali Mahdi broadcast a message Saturday night saying, ‘‘If anyone tries to interfere, we will cross by force.’‘

More guns were seen on the streets, and both sides reportedly were arming themselves.

There are fears Ali Mahdi wants to provoke conflict in hopes the 33-country U.N. peacekeeping force will be forced to intervene and renew its fight against Aidid.

U.N. sources said Ali Mahdi has refused their suggestions for less provocative routes for the march. U.N. troops no longer patrol Mogadishu’s streets and are visible mainly at fortified checkpoints outside their 11 strongpoints.

Peacekeepers are supposed to fire only when they are in danger, but an attack on U.N. troops could drag them into the fray. If U.N. forces then were overwhelmed, U.S. soldiers could be forced to intervene.

‘‘If there is a requirement for us to go on the ground, then we will do so and we will do so in force,’‘ U.S. military spokesman Col. Steve Rausch said.

An American army helicopter dropped fliers over the city on Sunday warning: ‘‘If any attempt is made against UNOSOM (U.N. Operations in Somalia) installations or its army, UNOSOM forces will take appropriate action.’‘

The demonstration also threatens to spark internal clashes in Aidid’s Somali National Alliance.

On Sunday, pickup trucks with armed guards toured south Mogadishu with megaphones, urging people to march. They were manned by dissidents from Aidid’s alliance who believe he is obstructing peace.

‘‘If anyone tries to create problems for those people coming from the north, we will fight you because we want peace,’‘ one message bellowed.

The planned march is a result of a U.N.-sponsored peace conference last week of leaders of the Hawiye clan, which includes Aidid’s Habre-Gedir and Ali Mahdi’s Agbal people.

The U.N. newspaper Maanta reported Sunday that Aidid militiamen have abducted three elders who attended the conference, including Habre-Gedir Chief Ahmed Rage.

Retired U.S. Admiral Jonathan Howe, the U.N. secretary-general’s special envoy, told reporters he was concerned about the kidnapping of a key figure with whom U.N. officials have pursued a new initiative to resolve Somalia’s conflict.

Rage ‘‘is very important to the restoration of peace not only in Mogadishu but throughout the country,’‘ Howe said.

U.N. officials have abandoned their hunt for Aidid, who is blamed for the killings of dozens of peacekeepers, in line with President Clinton’s decision to refocus on diplomacy and his criticism of the United Nations for personalizing the conflict.

Mogadishu has been relatively calm since Aidid declared a unilateral cease-fire Oct. 9 and released a captured U.S. helicopter pilot and a Nigerian peacekeeper.

The moves were designed to overshadow Aidid’s fugitive warlord image and enhance his political stature—a transition that clearly worries Ali Mahdi.

Ali Mahdi expressed concern Saturday about the new U.S. policy, saying Aidid is biding his time until American troops leave by March 31, taking the backbone out of the U.N. force.

Aidid has said Clinton’s plans to send thousands more soldiers to protect troops here are provocative.

About 300 artillerymen and engineers from the 24th Infantry Division arrived here Sunday from Fort Stewart, Ga., increasing U.S. troop strength to 6,900 ashore and 13,000 on ships offshore. The U.N. army has about 30,000 troops.