After a summit on Thursday evening, the 15-nation bloc "firmly condemned the coup attempt" in the country of two million people.

It added that a "stabilising support force" would deploy to Guinea-Bissau, without offering any further details.

Guinea-Bissau's presidency declined to comment on Friday when contacted by AFP.

On Tuesday, heavily armed men attacked government buildings in the capital Bissau where President Umaro Sissoco Embalo was believed to be attending a cabinet meeting.

The 49-year-old president emerged unscathed from a five-hour gun battle, later describing the attack to reporters as a plot to wipe out the government.

Eleven people, including four civilians, were killed, according to a government spokesman.

Guinea-Bissau is notoriously unstable, having suffered four military coups since independence from Portugal in 1974, its most recent in 2012.

The Economic Community of West African States (ECOWAS) also sent peacekeepers to the country in 2012 to guard public buildings among other duties. That force left when its mandate ended in 2020.

In 2014, Guinea-Bissau vowed to return to democracy, but it has enjoyed little stability since and the armed forces wield substantial clout.

The identity and motives of the attackers behind this week's attempted coup remain unclear. The army has launched a major probe.

Guinea-Bissau's government has also decreed a two-day period of national mourning for those killed in the attempted coup from Saturday.