KHARTOUM, Sudan, Jan. 24 - After rebuffing an attempt by President Omar Hassan al-Bashir of Sudan to become chairman of the African Union, African leaders today elected President Denis Sassou-Nguesso of Congo Republic to the position.

In doing so, the leaders sidestepped the embarrassing prospect of having Mr. Bashir, a leader accused of fomenting war in his own country, take the helm of a continent-wide organization that advocates peace.

Mr. Bashir, eager to rehabilitate his own image and that of his beleaguered country, had lobbied hard for the prestigious post. But after considerable behind-the-scenes jockeying over his proposal in advance of a two-day summit meeting that opened here on Monday, Africa"s leaders opted instead to set up a committee that today settled on Mr. Sassou-Nguesso.

He will replace President Olusegun Obasanjo of Nigeria as the African Union"s chairman.

African officials said that Sudan would be in line to assume the chairmanship in 2007, with the hope that the Darfur crisis will be greatly improved by then. Discussions on the plans for 2007 were continuing today.

American officials praised the African Union"s action. Jendai Frazer, the assistant secretary of state for African Affairs, called it "a very practical as well as pragmatic decision."

Selecting Mr. Bashir, a general who seized power in a 1989 coup, would have put the organization in the difficult position of attempting to mediate peace talks and quell the violence in the home of its chairman. Worse still, Mr. Bashir"s own government has been accused of carrying out attacks on civilians in the western Darfur region and arming militia fighters who continue to terrorize the population there. An international criminal court is investigating an array of officials in Mr. Bashir"s government for human rights violations related to the Darfur crisis, but has not indicated how high up the ladder the inquiry goes.

Human rights groups across the continent and beyond warned that choosing Mr. Bashir would damage Africa"s credibility in the eyes of the world and hamper the African Union"s efforts to negotiate an end to the Darfur crisis and to other conflicts around the continent.

"Making Bashir the chairman would be an insult to the victims of Darfur," Salih Osman, a Sudanese human rights lawyer and opposition member of Parliament, said before today"s decision. "The highest level officials in this government are involved in the atrocities in Darfur."

Sudan, celebrating the 50th anniversary of its independence, argues that it is working hard to bring peace to Darfur and that it has made enough progress on a number of other fronts that it deserves the chairmanship. A year ago, for instance, the government signed a power-sharing agreement with southern rebels that ended a two-decade-long conflict. Since then, the government has admitted former rebels into its ranks and opened up political space to opposition parties.

"Which country in Africa does not have internal problems?" asked Lam Akol, Sudan"s foreign minister, defending Mr. Bashir"s bid. Still, there are ample signs that Sudan has a long way to go. The government initially denied credentials to cover the summit meeting to a Sudanese newspaper that had editorialized against Mr. Bashir"s chairmanship bid. Authorities later backed down but said they would discuss the matter with the paper"s editor after the meeting ended.

On Sunday night, security officials broke up a meeting of several dozen human rights activists in which Mr. Bashir"s chairmanship was to be discussed. Participants were held for several hours and then released after various European ambassadors protested. "I"m surprised and disappointed," said Kent Degerfelt, the European Union"s ambassador to Sudan, who had several staff members at the meeting. "This is a step in the wrong direction."

The hesitancy to select Mr. Bashir was seen as clear evidence that the African Union, set up in 2002, is seeking to distinguish itself from its predecessor, the Organization of African Unity, which was criticized as a dictators" club unwilling to hold its members accountable. Already, the African Union has sanctioned two member states, Togo and Mauritania, for failing to hold democratic elections, and has conducted peacekeeping operations in Burundi and Darfur.

The Bush administration had suggested that Mr. Bashir"s selection might interfere in the African Union"s efforts to seek a peace settlement in Darfur. "It is a concern to us, and it should be a concern to the A.U. nations," President Bush said during a trip to Kansas on Monday.

The African Union"s first three chairmen, Thabo Mbeki from South Africa, Joaquin Chissano of Mozambique and Mr. Obasanjo of Nigeria, were chosen with little controversy. The 53-member bloc, loosely modeled after the European Union, rotates the presidency to give each of five regions access to the top post. East Africa says it is now its turn.