The five-year-old government of President Milton Obote of Uganda was toppled today in a military coup led by an Army general, Radio Uganda announced this morning.

Soldiers loyal to Brig. Basilio Olara Okello, whose forces mutinied in northern Uganda early this week and began a 150-mile march on the capital, drove trucks and buses into Kampala this morning. They were met with cheers and little resistance, the radio reported, and quickly seized control of the central bank, the parliament building and the government radio station.

The ouster of Obote, whose whereabouts were unknown tonight, ended the latest chapter in the torturous recent history of the East African nation, which was struggling, with limited success, to overcome the legacy of torture, mass killings and military attacks on civilians begun under the rule of dictator Idi Amin in 1971.

Deep-seated tribal resentment, which has complicated Ugandan politics since independence, appeared to play a key role in the ouster of Obote, a member of the minority Langi tribe. He was widely resented by the Baganda -- Uganda's largest and best-educated tribe -- for removing its traditional leader in 1966.

Radio Uganda reported a "bloodless coup" at 11:30 a.m. By afternoon there were reports of widespread looting by soldiers and civilians, and by nightfall western diplomats reported gunfire and explosions throughout Kampala. A series of explosions was reported at the Makindye barracks outside the capital, where soldiers yesterday had declared their loyalty to Obote.

The radio warned that looters would be dealt with severely and called on soldiers resisting the coup to surrender. Entebbe Airport was closed "until further notice."

Some reports indicated that Obote, who had ruled a nation increasingly riven in recent months by civil war, had fled to Kenya. Obote was overthrown by Amin in 1971, but became president again in 1980, a year after Ugandan rebels and Tanzanian Army troops ousted Amin.

In telephone interviews with Reuter and The Associated Press, Amin, who lives in Jeddah, Saudi Arabia, welcomed the coup. He told AP that he had known about plans for the coup "several months ago" and that its organizers briefed him Friday afternoon.

["I support the coup," Amin told Reuter. "I call on all members of the armed forces to reunite, and I am ready to rescue Uganda."]

Obote's wife, Miria, who had been attending the U.N. women's conference here, remained in seclusion, under Kenyan military guard, in Uganda's diplomatic mission in Nairobi. A Ugandan here with contacts in Kampala said that Obote last was seen in the Ugandan capital at 9 p.m. Friday.

One week ago, responding to growing disquiet within the Army and the growing threat of a five-year-old rebel movement led by Yower Museveni, Amin's former defense minister, Obote was reported to have told senior Army officers, "if you want to take over this chair you can bring your guns and take it, but it is very hot."

Last night, Radio Uganda quoted him as appealing to political and religious leaders to try to restrain the Army rebellion in the north, Agence France-Presse reported.

The radio said today that the coup would mark an "end of Obote's tribalistic rule." When he came back to power in 1980, Obote was accused by the Baganda and the northern Acholi tribe of stealing the general election. Coup leader Okello belongs to the Acholi, the dominant tribe in the Army.

On Radio Uganda, a second lieutenant who had announced the coup earlier in the day later called on Museveni, the former defense minister who heads the National Resistance Army guerrilla movement, to "report immediately to Kampala . . . for the immediate reconstruction of our nation." Coup leaders apparently would like to integrate the rebels into the new government.

[In Stockholm, where he is visiting his wife and children, Museveni said in a Swedish radio interview that the coup was a "positive development," but he did not commit himself to returning to join forces with the coup's leaders.]

During the looting spree in Kampala today, witnesses reported soldiers entered the offices of the United States Information Service, shooting out four windows and forcing five Americans to barricade themselves on the second floor. [The State Department said in Washington later that all U.S. personnel were safe.]

The economy that Obote inherited in 1980 had been all but destroyed by the rule of Amin, who human rights groups have said was responsible for the deaths of about 300,000 Ugandans.

According to a report last year by Elliot Abrams, then assistant secretary of state for human rights, the Ugandan Army has been responsible for the deaths and disappearances of as many as 200,000 civilians. An Amnesty International report last month detailed what it called "widespread and systematic use of torture against detainees."