Intense fighting has erupted in western Ivory Coast, where fighters loyal to two rival presidents are battling for control of Duekoue, a strategic town.
Residents of Duekoue reported hearing explosions and heavy weapons being fired on Monday.
Witnesses say fighters backing internationally-recognized president Alassane Ouattara launched an attack to capture the town from forces of incumbent president Laurent Gbagbo.
Pro-Ouattara rebels have been making gains in western Ivory Coast, seizing at least five towns from pro-Gbagbo troops in recent weeks.
Gbagbo has defied intense international pressure to turn over power to Ouattara, who the United Nations and African Union recognize as the winner of last November's presidential election.
The town of Duekoue is located at a crossroads that leads to either Liberia in the west or Guinea in the north.
The U.N. refugee agency says up to one million people have fled their homes because of post-election violence in Ivory Coast.
The United Nations says at least 462 people have been killed in violence since the crisis began in December.
The U.N. Security Council will take up a resolution this week that seeks sanctions against Gbagbo and his closest advisors.
Some information for this report was provided by AFP and Reuters.