At least 20 deaths have been reported in the latest fighting along the tense border between Ivory Coast and Liberia.
Heavy fighting has erupted in recent days on both sides of the Ivorian-Liberian border, a region where rebels fighting both governments have been active.
The defense minister of Liberia, Daniel Chea, is accusing the Ivory Coast military of supporting Liberian rebels fighting his armed forces. Mr. Chea says this amounts to "a declaration of war."
Mr. Chea says Liberia could send troops into Ivory Coast on a counter-attack, after Ivory Coast helped rebels who attacked the Liberian border town of Toe on Friday.
An Ivorian army spokesman, Colonel Jules Yao Yao, has issued a statement denying the Liberian charge. However, he concedes Liberian rebels are camped in parts of the western border region beyond the control of the Ivorian armed forces.
In the same statement, Colonel Yao responded to allegations by an Ivorian rebel group that Ivorian helicopter gunships killed 20 civilians in an attack near the western town of Bin-Houye on Saturday.
Colonel Yao says the army had been counter-attacking a force of heavily armed men speaking English, the official language of Liberia. He said anyone killed in the fighting would have died in combat.
The fighting is a sign of the fragility of Ivory Coast's cease-fire, as a stalemate drags on over the formation of a new government that would include rebel representation.
President Laurent Gbagbo continues to resist rebel demands that they be given control of the defense and interior ministries. The rebels say they were promised those portfolios during peace talks in January.
Mr. Gbagbo refused to discuss the political crisis at a news conference Saturday.