Army troops in the West African country of Ivory Coast seized control of the capital, Abidjan, today and proclaimed a military government, an uprising unprecedented in a country long considered one of Africa's most stable.

Soldiers began seizing government installations Thursday in what they said was a mutiny by an Abidjan-based unit over unpaid wages. Today, the former army chief of staff, Gen. Robert Guei, announced on state television that President Henri Konan Bedie was no longer in power. But Bedie said later in a radio interview that he retained power and was meeting with mutinous troops.

Bedie appealed for popular resistance to the coup, but poor people in Abidjan's vast slums cheered his reported overthrow, said residents. Bedie's Democratic Party of Ivory Coast--the only party that has ruled there in nearly 40 years of independence--has lost support in the past decade over official corruption and rising demands for real democracy.

Still, as some senior military officers and foreign diplomats reportedly implored Guei to halt the coup, independent observers found reason to hope that the crisis might be resolved peacefully. Ivory Coast--known officially by its French name, Cote d'Ivoire--has a large, educated middle class and civil society unlikely to support military rule.

The strongest reason for optimism lay in how strongly the flavor of events once so common to transfers of power in Africa--dueling broadcasts, mutinous soldiers firing automatic weapons into the air and a man in uniform declaring the constitution null and void--now seemed out of place.

Since the end of the Cold War, coups have become less frequent in Africa and, indeed, have never occurred in Ivory Coast. Self-appointed rulers who once could count on the United States or the Soviet Union to prop them up must answer to an array of Western donors, starting with the International Monetary Fund and World Bank. And their primary condition for foreign aid is at least the appearance of democracy.

"That's the new atmosphere," said Herman J. Cohen, a former assistant secretary of state for Africa. "This general on the television doesn't seem to realize that."

Ivory Coast, long ruled by the French troops and bureaucrats who created it, has remained one of France's most loyal former colonies in Africa. Its founder, Felix Houphouet-Boigny, ruled the country tightly for 33 years, permitting opposing political parties only when he could no longer prevent them without heavy bloodshed. Bedie, a bland machine politician in the ruling party, took power when Houphouet-Boigny died in 1993.

Bedie won a disputed election and rode out protests and riots in 1995 after disqualifying his chief opponent. Soon after, Bedie dismissed Guei as army chief; officials alleged that Guei had been plotting a coup.

On Thursday, soldiers drove into the state television station and fired into the air when some employees resisted orders to leave. Some of the employees fled to the U.S. Embassy's cultural center around the corner, and told Washington Post researcher Solomon Ababio that the troops were demanding back pay for their unit's service in a U.N. peacekeeping mission in the Central African Republic.

In numerous parts of Abidjan, soldiers looted shops and were joined by impoverished civilians, residents said. No deaths were reported.

Guei appeared on state television today, saying he had taken power at the troops' request. "From this instant, President Henri Konan Bedie is no longer the president of the republic," he said, and proclaimed the dissolution of parliament and other government institutions. A Military Committee of Public Salvation announced a dusk-to-dawn curfew and called on soldiers to cease looting.

From a hiding place in the city's diplomatic neighborhood, Bedie responded in an interview on Radio France Internationale. He called on Ivorians to "resist and oppose this grotesque and retrograde military coup by all means possible," and vowed to remain at his post. He pledged to resolve the pay demands of the soldiers through "dialogue."

An American reached by telephone in Abidjan described the mutineering soldiers as raucous, but said residents were calm. "There are [soldiers] roaring through the streets looking pretty ugly, with cars that have obviously been stolen," the resident said. "All the danger is potential danger, but the potential danger is there."

The Christmas Eve crisis followed months of mounting opposition to Bedie. Like virtually all black African states created as European-ruled colonies, Ivory Coast is an artificial mix of ethnic groups. While Houphouet-Boigny ran an authoritarian government, he assiduously dampened ethnic tensions, partly by distributing wealth from the cocoa farms that are the pillar of the economy.

But cocoa prices have fallen and the economy has struggled to keep up with a flood of immigration from Burkina Faso, Mali, Liberia, Ghana and other neighbors. In 1995, Bedie--an ethnic Baoule from the country's center--alienated many Muslim northerners by disqualifying northerner Alassane Ouattara from the presidential race, and tensions over that issue have revived as Bedie faces reelection next fall.

"For a place where things are good, things are bad at the moment in Ivory Coast," said I. William Zartman, director of African Studies at the Johns Hopkins University's School of Advanced International Studies.

He said the coup could yet be reversed or result in a more even-handed election than Bedie was prepared to allow.

Correspondent James Rupert contributed to this report.