Sao Tome and Principe's toppled president Fradique de Menezes appealed for international help Wednesday after he was ousted in a military coup while on a visit to Nigeria.
"I am now making a strong appeal to all democrats, world leaders and African leaders to help us stop this kind of procedure," Menezes said at the Leon Sullivan Summit in Abuja, a meeting between leading Africans and African-Americans.
"Africa cannot attain greatness with bad governance, corruptionand coups d'etat. We must toe the path of democracy, good governance, transparency and civil liberty," he said.
The government of Sao Tome and Principe was overthrown by the military, apparently in alliance with a small political party, Portuguese news agency Lusa reported.
The coup leaders said the action is "a reflex of the difficult social-economic conditions" that the country is facing and the "political instability" caused by the former regime.
Lusa said senior members of the small Democratic Christian Front (FDC) party were seen as assisting troops at the army barracks in the capital where most detainees are being held.
The FDC has recently planned demonstrations against the Sao Tome government, which was accused of corruption. The party was formed in 1990 and many of its current leaders were involved in anearlier coup attempt.
The military coup was led by Maj. Fernando Pereira "Cobo", chief of Sao Tome's military academy.
There were no reports of casualties in the military coup and few people ventured onto the streets. Troops took over the country's central bank and broadcast media.
Prime Minister Maria das Neves, the country's first female premier, was detained, together with other senior officials, including Parliament Speaker Dionisio Dias, Defense Minister Fernando Daqua, and Public Works and Natural Resources Minister Joaquim Rafael Branco.
Other members of government and MPs were ordered to report to police stations in a military radio broadcast.
The impoverished nation has recently raised its international profile after reaching a joint oil exploration deal with Nigeria.
In recent months, arguments over the oil licensing process and distribution of revenues have sparked political and social strife in the country.