ZAIREAN President Mobutu Sese Seko, ceding some power after 26 years of autocratic rule, met yesterday with opposition leaders to try to agree on how to share Cabinet posts.The beleaguered president fired his Army chief Sunday and asked opposition leader Etienne Tshisekedi to form a crisis government. In a move that ended a week of chaos and looting, Mr. Mobuto agreed to the choice of Mr. Tshisekedi, who was interior minister until he split with Mobuto. Tshisekedi has been his fiercest adversary since 1980. Tshisekedi's aides said he had accepted the challenge of trying to steer Zaire through crisis in an uneasy tandem with Mobutu. The two sides were to meet for the third successive day to try to agree on Cabinet posts. A joint statement issued Sunday night said Tshisekedi would be formally invested by parliament - still an exclusive preserve of Mobutu supporters - before being presented to Zaire's national conference on democratic reform. The opposition has clearly dropped its earlier demands that any new government must be approved by the conference. The statement said the new government would be "presented" to the 3,000 delegates, many of whom say Mobutu must resign. Military sources said Mobutu had ordered a restructuring of the armed forces, since soldiers led much of the looting that ravaged the country last week. State radio said 117 people had been killed and more than 150 injured in the unrest. Gen. Manzembe Mayibanga was replaced by the head of military intelligence, Gen. Mahele Liyeko, because of his failure to control the armed forces, said an official statement. General Liyeko appealed to the Army to "leave politics to the politicians" and to respect the law and property. He persuaded paratroopers who seized Kinshasa airport yesterday after a looting spree to leave. A dusk-to-dawn curfew imposed this week was lifted. Mobutu and his supporters at the talks at first refused to accept Tshisekedi to replace Prime Minister Mulumba Lukoji. But the opposition's "sacred union" alliance stood firm, and a committee of "wise men," including Mobutu, eventually agreed. Although Mobutu has been forced to cede some authority for the first time since he took power in 1965, only major opposition parties are involved in talks on a new government. Angry national conference delegates shouted "Thieves, looters!" at the opposition's motorcade as it swept into the grounds of the Marble Palace. Any new government faces an economy in tatters and widespread corruption, and Western governments are pressing for major changes in the way Zaire is run.