One police officer has been killed in the capital of Guinea-Bissau, a resident of Bissua has told BBC Focus on Africa radio.
It follows reports of gunfire near where President Umaro Sissoco Embaló and Prime Minister Nuno Gomes Nabiam were having a meeting.
The resident told Focus on Africa that the firing had now subsided and had actually occurred at a ministerial building, not the presidential palace as had been reported.
AFP earlier reported that people had been seen fleeing the area close to presidential palace and that the local markets were closed and banks shut their doors, while military vehicles laden with troops drove through the streets.
The current whereabouts of President Umaro Sissoco Embaló and Prime Minister Nuno Gomes Nabiam are unknown, the source says.
According to the witness, the military and police went to the scene where the armed men were firing, following which a police officer was shot.
Soldiers are patrolling the streets of Bissau in military vehicles and some calm has returned.
Guinea-Bissau has a long history of political instability and military coups, the last of which was in 2012.
