President Joao Bernardo Vieira of Guinea-Bissau, shown here in 2006, died early Monday morning. (Thierry Charlier/Associated Press)

Renegade soldiers killed the president of Guinea-Bissau just hours after a bomb blast led to the death of his rival, according to senior government officials.

President Joao Bernardo Vieira died early Monday morning, Luis Sanca, security adviser to Prime Minister Carlos Gomes Jr., confirmed for the Associated Press. Sanca declined to provide further details on the death.

Gunfire had been heard around the presidential palace in the capital of Bissau for several hours overnight in the fragile West African nation, according to witnesses. But the capital was calm on Monday, officials said.

Vieira had ruled Guinea-Bissau for 23 of the past 29 years. He came to power in a 1980 coup, but was forced out 19 years later at the onset of the country's civil war. He later returned from exile in Portugal to run in the country's 2005 election and won the vote.

Under the constitution, parliament chief Raimundo Pereira succeeds the president in the event of his death.

The Portuguese news agency LUSA reported that troops attacked Vieira's residence with rockets and rifles on Sunday night.

Troops closed roads around the armed forces building in Bissau on Sunday and a blast apparently destroyed part of the building, according to the BBC.

'The situation is under control': military spokesman

Guinea-Bissau's armed forces chief, Gen. Batiste Tagme na Waie, was reported killed by the bomb. Waie was considered a political rival of Vieira.

A coup is not occurring, said military spokesman Zamora Induta, who was among military officials who met with the government cabinet on Monday.

"We reaffirmed our intention to respect the democratically elected power and the constitution of the republic," Induta said. "The people who killed President Vieira have not been arrested, but we are pursuing them. They are an isolated group. The situation is under control."

The military also dismissed claims that Vieira had been killed in retaliation for Waie's death.

The African Union condemned the killings on Monday, calling them "cowardly and heinous attacks which have come at a time of renewed efforts by the international community to support peace-building efforts in Guinea-Bissau."

Guinea-Bissau has had multiple coups and attempted coups since 1980. The country is considered to be a key transit point for cocaine smuggled from Latin America to Europe.

With files from the Associated Press