African Union chief Jean Ping said Wednesday that normality had returned to Guinea-Bissau two days after the troubled west African state's army chief claimed to have foiled a coup.

Ping paid a brief visit to Bissau in the wake of the foiled coup and clashes which followed overnight and Tuesday, saying the situation was "a source of concern" for the African Union.

"In light of my different meetings I think that the situation has now normalised," Ping told journalists, adding he was "optimistic" as he left the country for Banjul, Gambia.

"Dialogue must be maintained between authorities, politicians, civilians and soldiers so that together, they can maintain peace, stability and national harmony."

Ping held talks with Speaker Raimundo Pereira, the interim head of state in the absence of President Malam Bacai Sanha, who is currently undergoing medical care in France.

The AU chief also met with Prime Minister Carlos Gomes Junior.

On Monday, Guinea-Bissau's army chief, Antonio Indjai, said loyalist forces had thwarted a coup bid masterminded by the country's navy chief, Jose Americo Bubo Na Tchuto, who is now under arrest.

Bubo Na Tchuto has already been accused of plotting a coup but on that previous occasion was cleared of the charge. But in 2010 the United States named him on a list of the country's alleged drug barons.

On Tuesday night, one soldier was killed as troops combed the seaside capital for suspected coup-plotters and a police commander wanted over the alleged rebellion was subsequently shot dead.

One rights group said Wednesday the police commander, Yaya Dabo, had been about to turn himself in when police opened fire on him, denouncing his killing as a murder.

On Wednesday, the Democratic Opposition, an alliance of 14 opposition parties, issued a statement condemning any attempt to overthrow the government by violence.

Guinea-Bissau's history, since independence from Portugal in 1974, has been studded with coups, mutinies and political murders.

The small state has also become a drug-trafficking hub, mostly for cocaine from South America to Europe.

Two dead as Bissau troops hunt 'failed coup' suspects
Bissau (AFP) Dec 27, 2011 - The day after Guinea-Bissau said it had foiled a coup attempt, clashes between security forces and alleged mutineers left at least two people dead, army and police sources said Tuesday.

Joint teams of soldiers, police and paramilitary police were hunting suspects in what Prime Minister Carlos Gomes Junior has said was an attempt Monday morning to launch a coup d'etat, military sources said.

A police commander who had been wanted as a suspect in the rebellion was shot dead Tuesday night, a police source said. The previous night a soldier died in a clash with renegade forces, according to an army officer.

United Nations chief Ban Ki-moon and EU foreign policy chief Catherine Ashton condemned the violence in the impoverished country that has a history of coups and army mutinies and has become an illegal drug-trafficking hub.

The latest turmoil in the West African nation started early Monday when renegade forces attacked the army headquarters while President Malam Bacai Sanha was abroad, receiving medical treatment in Paris.

No-one was reported killed in the initial clash, which saw renegade troops seize a cache of weapons, according to the army. Some of the attacking soldiers said the unrest was over a pay dispute.

The army chief later said the navy chief -- Rear Admiral Jose Americo Bubo Na Tchuto, previously accused of coup plans and of links to the drugs trade -- had been arrested as the "mastermind" of the coup attempt.

Long thought close to the army chief, General Antonio Indjai, navy chief Bubo Na Tchuto had reportedly fallen out with him, and some observers surmised that the unrest involved a settling of scores.

Foreign Minister Mamadu Djalo Pires said Tuesday: "There will be investigations, and those identified will be brought to justice."

Among suspects being pursued were lawmakers and former ministers of the ruling African Party for the Independence of Guinea and Cape Verde who are reportedly opposed to Prime Minister Gomes Junior.

Troops combed the capital after the alleged coup attempt and clashed with renegade forces on Monday night, an army officer said.

"We had gone to Luanda (district) to arrest a group of suspects," an army captain told AFP on condition of anonymity. "They were armed and opened fire on my men; I lost one and two others were wounded."

Another firefight that lasted close to three hours erupted in the capital's Antula neighbourhood overnight, military sources and witnesses said.

"In Monday morning's attack, many soldiers were able to make away with weapons and ammunition. My task was to recover the weapons and arrest the suspects," another military commander said.

"But they offered resistance and I had to resort to heavy equipment, including bazookas," he said, without elaborating on the identity of the suspects or any casualty toll.

Troops also raided the home of a ruling-party lawmaker thought to be harbouring mutineers, and the operation turned up a "veritable arsenal" of weapons, Interior Minister Fernando Gomes said.

On Tuesday evening a police commander suspected of involvement in the alleged coup attempt was shot dead in the capital.

The officer -- identified as Yaya Dabo by a police source who asked not to be named -- was killed outside a police station near the city centre, said an AFP journalist who saw the bullet-riddled body.

The police source said Dabo was killed in a firefight and had been on a wanted, while a witness, who spoke to AFP on condition of anonymity, said the police commander had arrived apparently to surrender.

United Nations chief Ban Ki-moon on Tuesday condemned the violence.

"The secretary-general condemns the use of force to settle differences in Guinea-Bissau," Ban's spokesman Martin Nesirky said.

"The secretary-general also encourages the authorities of Guinea-Bissau to respect due process in the investigation of the reported events."

EU foreign policy chief Catherine Ashton was "deeply concerned by yesterday's violent actions in Guinea-Bissau by some elements within the military", a spokesman said in a statement.

"She condemns in the strongest possible terms such anti-constitutional actions.... Violent attempts against constitutional legality cannot be allowed, and must stop."