Ethiopia, a close ally of the United States in anti-terrorism efforts, has cracked down on the opposition, especially after disputed elections in 2005.

Those found guilty on Monday by an Ethiopian court were among 131 opposition leaders, journalists and civil society activists charged in December 2005 with treason, inciting violence and attempting to commit genocide.

They could face the death penalty when sentenced, which local media said would take place next month.

U.S. State Department spokesman Sean McCormack said the United States was looking into whether the court’s action was in accordance with Ethiopia’s constitution and law.

“It would appear that this is a peremptory action that was taken by the court that surprised not only us but the defendants, as they were working to mount a defense against these charges,” said McCormack.

“Suffice to say, it is something we’re very surprised about, quite concerned about and watching very closely,” he added.

A former professor from Norfolk State University in Virginia, Yacob Hailemariam, was among the opposition leaders convicted in Ethiopia, the State Department said.

Hailemariam was a former prosecutor for the U.N.’s tribunal on war crimes in Rwanda and returned to Ethiopia in 2005 to take part in the elections.