Rebels Install Ex-Member of Parliament as President : Somalia: Mahdi pledges democracy and invites other guerrilla groups to help run the country. The capital is in ruins.

In an informal ceremony punctuated by gunfire, victorious rebels Tuesday inaugurated a new president and vowed to hunt down deposed dictator Mohamed Siad Barre.

Ali Mahdi Mohamed, 52, installed by the insurgent United Somali Congress, promised democracy, invited other powerful rebel groups to join in running the country and said that he would appeal for international aid to restore an economy shattered by years of corruption and warfare.

Gunshots, presumably fired in celebration, resounded continually from outside as the ceremony unfolded in a waiting room at the national police headquarters. Four dozen supporters crowded the room, breaking into chants of “Allah Akbar” (God is Great) and punching their fists into the air after Mahdi had placed his hand on a Koran and taken the oath of office.

Mahdi, a hotelier and former member of Parliament credited with a central role in organizing the United Congress’ uprising in the capital, said the new regime wants to bring Barre to trial. The deposed president, who ruled Somalia for 21 years, fled Saturday to end a month of heavy fighting that destroyed much of this once-graceful seaside capital. Conflicting and unconfirmed reports Tuesday said that Barre had arrived in neighboring Kenya, but this was denied by senior officials there.

“We are after him, we have sent troops to capture him,” Mahdi said in reply to questions. He said that Barre and a small group of loyalists had fled south toward the port of Kismayu. A day earlier, military vehicles and flashes of what appeared to be gunfire could be seen from the air above the Mogadishu-Kismayu road.

Mahdi pledged that the United Congress, one of three major groups that fought against Barre, would enlist other factions in the interim government. He promised elections, but could not offer a date.

As he spoke, the city around him was in profound collapse, presenting an unsettling catalogue of the tragic and grotesque.

At one street corner, two long-beaked ibis pecked at misshapen brown bundles that, upon a close look, turned out to be the cloaked bodies of 16 civilians. Most had their hands tied behind their backs, and all had turned leathery and brittle under the tropical sun.

A few hundred yards away the bodies of eight soldiers from the defunct government lay in two clusters on the road. Somebody had sprinkled lime upon the corpses, lending a whitish-gray pallor to the scene. A small boy unconcernedly rode his bicycle between the clumps of bodies.

Throughout the city roamed hundreds of young men in sandals and slacks or sarong-like wraps, carrying an unlikely assortment of guns. Pistols, single-shot bolt action rifles, the ubiquitous AK-47, other assault rifles, grenade launchers, anti-tank weapons--all were carried on the street and brandished casually.

The array of weapons and a lack of discipline made for a spectacular fireworks show at night. By the now-fetid pool of the shelled and abandoned Guled Hotel, visitors watched red tracer rounds float skyward for hours, arcing up past a palm tree and a crenelated roof toward a full white moon. The display unnerved visitors but seemed a joke to United Congress partisans. One of them, Mohamed Hohassan, asked with a laugh: “Do you feel secure?”

The guerrillas do, having survived Barre’s second assault on his own people in three years. In 1988 Barre loosed his air force upon northern cities that had entered into a separate rebellion, and Western human rights groups say that the aerial bombardment killed thousands. After warfare with the United Congress broke out on Dec. 30, according to the rebels and to Westerners who stayed on through the fighting, Barre’s forces retreated to the airport on the outskirts of town and to the fortified presidential mansion downtown and released indiscriminate artillery barrages.

In the hardest-hit neighborhoods, few houses or shops escaped gaping holes caused by shells or the pockmarks of machine-gun fire. The damage extends across the city, now a chaotic tableau of shattered tree limbs, rubble, burned out buildings and crushed cars.

Once the fighting began, many of the wounded made their way to the only hospital to stay open during the fighting, one run by the European charity SOS Kinderport International. Asked how many people had been injured, hospital director Huber Wilhelm said: “Uncountable. There were at least 150 coming in per day.”

On Tuesday, the hospital’s tile floor was thick with congealed blood. A 3-year-old boy screamed, the top of his left foot ripped open from his ankle to his toes by a stray bullet. Wounded groaned in pools of blood by the courtyard, where four bodies lay awaiting burial. Across the street in sandy soil were shallow mounds, makeshift graves that were evidence of the 20 to 30 people Wilhelm said had died each day in the hospital.

Downtown, looters in a steady stream went about their business, carrying a startling array of goods--chairs, desks, sponges, a sink, tires, books--from broken shops and homes. In the lane behind the ransacked central bank, there was a bizarre scene: dozens of men squatting at curbside, combing through shin-high mounds of faded bank notes. A few yards away, at the shelled and gutted Roman Catholic cathedral, men with a heavy truck had hitched a cable to the church’s electrical generator and were patiently maneuvering it from a small courtyard.

On the outskirts of town was the $35-million high-security U.S. Embassy, abandoned on Jan. 5 and sacked by government troops the next day. On Tuesday, an unseen looter hammered at something in the dark and fire-blackened upstairs, while the reams of computer paper and reports that littered the ground floor remained undisturbed.