The army of Yoweri Museveni, the guerrilla leader who proclaimed himself president of Uganda in late January, reportedly has overrun the last remaining stronghold of the previous military government.

The taking of the northern town of Gulu, where 5,000 soldiers loyal to the former government were believed to have assembled to make a last stand, would give Museveni's National Resistance Army control of nearly all of Uganda. Radio Uganda reported today that Gulu was overrun yesterday after three hours of heavy fighting.

A victory at Gulu would mark the climax of Museveni's five-week march north from Kampala. In a country ravaged for nearly two decades by north-south tribal hatred, Museveni's southern-based government has garnered the support of many northern Ugandans -- even as his soldiers have routed former government forces, almost all of whom are members of northern tribes.

The reason behind Museveni's reception apparently has been the disciplined behavior of his soldiers. Troops loyal to the former government, as they fled Museveni, had looted scores of towns, killed several hundred civilians and burned crops.

Museveni's army, by contrast, was under orders to protect the property and lives of civilians. The president has said that his standing order to his troops is this: "You kill a civilian, we kill you." Western diplomats in Kampala say that, for most part, the troops have followed orders.

The commander of the former government's troops, Basilio Olaro Okello, had vowed to make his last stand in Gulu, the capital of his Acholi tribal homeland. Western diplomats in Kampala said that prior to Museveni's taking of the capital, Okello had ordered the transport of a large cache of arms and ammunition north to Gulu.

There was no word today on the fate or whereabouts of Okello, who had been second in command of the short-lived military regime that came to power last July by toppling the government of president Milton Obote. Officials in Museveni's government have said that Okello, if captured, will be tried by a special tribunal on charges of genocide.

During the early 1980s, Okello was in charge of Obote's troops in the Luwero Triangle area north of Kampala, where tens of thousands of civilians reportedly were killed by government soldiers in retaliation for rebel attacks. During the past month, Museveni has conducted press tours of mass graves found in the area.