Throughout the night and into Friday morning, gunfire erupted in Bissau during confrontations between members of the national guard and presidential guard special forces.
The gunfire ensued following the release of two government members by national guard soldiers, who had been questioned by the police on Thursday.
The two men had been summoned by the judiciary on the same day and taken into custody.
Police questioned them for several hours about a withdrawal of $10 million from state coffers, according to military intelligence.
The small west African nation of Guinea-Bissau has been politically unstable since 1974, going through four coups and several attempted coups.
Preisdent Umaro Sissoco Embalo, appointed two generals in September, Tomas Djassi and Horta Inta, as head of presidential security and chief of staff respectively.
The reinforcement of presidential security comes at a time when coups or attempted coups are multiplying in West Africa, including in Gabon, Niger, Mali, Burkina Faso, Guinea and, last week, Sierra Leone.