Calm has returned to Bissau, the capital of Guinea-Bissau, after the overnight killing of the tiny West African country's army chief and President Joao Bernardo Vieira, sources told Xinhua on telephone.

A source close to the Presidential Office who gave his name only as Bernabe said armed forces are being positioned in the streets of Bissau, where the situation is under control.

At noon, the government broadcast on state radio the deaths of both President Vieira and the army chief of staff, Batista Tagme Na Wai.

This was the first official announcement after Zamura Induta, chief of external relations of the army, told a press conference that President Vieira had been killed in a back-to-back attack.

An unknown number of soldiers apparently launched a retaliatory strike after Na Wai was killed in an explosion that destroyed part of the military headquarters late on Sunday.

President Vieira "was killed with his driver by a group of militia close to chief of staff Tagme Na Wai at the moment when he attempted to flee his residence early morning, about 4 a.m. (0400 GMT)," Induta declared.

The armed forces have voiced loyalty to the government and the Constitution after both men were killed.

Witnesses have reported no looting or chaos since Monday morning, although city traffic is being banned with only military vehicles are seen moving around.

Vieira, 70, was the longest serving president in Guinea-Bissau since its independence from Portugal in 1974. He came to power in a military coup in 1980 before overthrown in the 1998-1999 civil war after ruling the country for 19 years. He returned to power in 2005 after winning the presidential election.

In January, Na Wai filed a complaint against Interior Minister Cipriano Cassama, accusing him of ordering the presidential guard to shoot at him.

Na Wai said "elements, who supported President Joao Bernado Vieira during the 1998-1999 civil war, were recently integrated into the presidential guard," who opened fire at him "on Jan. 4, around midnight, under the orders of the Minister of Interior Administration, Cipriano Cassama."

The army chief was known as a critic of President Vieira's policy, including some of his appointments. He had served in a military junta that toppled Vierira in the civil war.

The African Union and the Economic Community of West African States (ECOWAS) on Monday condemned the assassination of President Vieira. The ECOWAS denounced the killing as "assassinating democracy."

The international community placed high hope on the country's legislative election held in November, seeing it as an opportunity to lead its 1.5 million population out of the long-standing instability. But the killing proved a blow to the hope of post-election stability.

(Xinhua News Agency March 3, 2009)