ADDIS ABABA, Ethiopia (AP) — The Ethiopian government says it has arrested an opposition figure for violating the terms of a state of emergency declared in October.

The state-affiliated Fana Broadcasting Corporate reported Thursday that Merera Gudina is under investigation for having met with the leader of an outlawed group while he traveled in Belgium recently.

Merera was arrested when he returned to Ethiopia on Wednesday.

Merera has been a government critic for more than a decade and hails from the restive Oromia region, which has seen anti-government protests since November 2015. He is the vice chairman of the Ethiopian Federal Democratic Unity Forum, one of the biggest opposition groups in Ethiopia.

Amnesty International said Thursday that Merera's arrest is "an outrageous assault" on the right to freedom of expression in Ethiopia.