Kinshasa, Congo ? Congo arrested a group of foreign security guards, including three Americans, on suspicion of plotting a coup ahead of national elections, a government official said Wednesday.

But a United Nations official cast doubt on the claim and said the U.N. was confident the country would remain calm for the vote, set for July 30.

The suspects arrested Tuesday were former soldiers who worked for a Congolese security company, Interior Minister Theophile Mbemba said.

They “were working in Kinshasa as security guards but it is clear that they were military personnel with political plans,” Mbemba said. “They were part of a coup attempt, and they will face justice in Congo.”

He said there were three Americans, 10 Nigerians and 12 South Africans among the group of 32 taken into custody.