DAKAR, Senegal — A court in the increasingly isolated West African nation of Mali sentenced 46 soldiers from neighboring Ivory Coast to 20 years in jail on Friday, after the military junta that runs Mali accused them of being mercenaries.

The government of Ivory Coast said the soldiers were in Mali to support the United Nations peacekeeping mission, a force of 15,000 members that has been there for almost a decade to protect civilians from violent Islamist groups. But the Court of Appeal in Mali’s capital, Bamako, convicted them of crimes including conspiracy against the government, after a closed trial that lasted a day and a half.

Mali, home to ancient empires and centers of learning, earned praise from Western countries just a decade ago as a beacon of stability and democracy in the region. But the arrest and trial of the soldiers from the Ivory Coast is only the latest indication of the strained relations between Mali and its neighbors, international partners and even the U.N. mission tasked with restoring stability.

“It is a difficult decision to bear,” said Moussa Traoré, the representative of Ivory Coast’s ruling party, who was in Bamako after the proceedings ended. “These are soldiers who are in the regular army of Ivory Coast.”