Rwanda has arrested four generals, accusing them of illegal business dealings across the border in the mineral-rich Democratic Republic of Congo, an army spokesman told Reuters on Wednesday.

“They are under investigation for acts of indiscipline with respect to getting involved with civilians in business dealings in the Democratic Republic of Congo,” Colonel Joseph Nzabamwita, a spokesman for the Rwanda Defence Force told Reuters.

“They have been suspended from duty and placed under house arrest,” he said.

A diplomat said the detentions might be linked to the publication of a U.N. report last month on illegal smuggling of minerals between Congo and Rwanda using illegal border crossings.

Nzabamwita named the four as Fred Ibingira, Richard Rutatina, Wilson Gumisiriza and Dan Munyuza.

These are among the most high profile military arrests since two generals were arrested for corruption and misconduct in April, 2010. Other top brass and officials have fled into exile after falling out with President Paul Kagame.