A group of men invaded the Sao Tome and Principe military headquarters on Thursday night, RFI reported on Friday.
The attack, which the government called as a "coup d'etat", was being neutralized on Friday morning.
"I want to tell the people of Sao Tome and Principe, those residing in the country and the foreign community, that the situation is under control, it is calm," Sao Tome and Principe's Prime Minister Patrice Trovoada said at a press conference on Friday.