One person died and several others were injured overnight when soldiers shot at the presidential residence in what appeared to be a coup attempt shortly after parliamentary election results were announced in the small West African nation, the BBC reported.
Shola Omeregie, a representative for the United Nations in Guinea-Bissau, confirmed to the broadcaster that there had been a military attack on the president's home but that Vieira and his family were safe.
The African Union issued a warning against any "attempt to seize power by force" in the former Portuguese colony, which has a recent history of coups. The violence came after the ruling party won the parliamentary balloting by a wide margin, the BBC said.
The interior ministry confirmed that one attacker was killed while several guards loyal to the president had been injured.