An Ethiopian opposition leader has been arrested in the capital Addis Ababa and his home and office searched, his party said on Tuesday.
Ethiopian Citizens for Justice (Ezema) president Chane Kebede, an ethnic Amhara, was arrested on Sunday while sitting at a cafe with a friend and remains behind bars, the party's head of legal and organisational affairs Seyoum Mengesha said.
"We do not know exactly why he was arrested," Seyoum told AFP. "There are rumours it may be related to the violence in the Amhara region and the current state of emergency."
The government of Prime Minister Abiy Ahmed imposed a six-month state of emergency in Amhara in early August after fighting erupted between federal forces and a local militia known as Fano.
The measure gives the authorities sweeping powers to arrest people, impose curfews and ban public gatherings.
Ethiopia's rights body has accused federal forces of carrying out extra-judicial killings in Amhara as well as mass arbitrary detentions under the state of emergency.
Seyoum said Chane's arrest did not comply with "constitutional procedures" and that he was taken away by unknown people in a vehicle without licence plates.
Security forces also searched Chane's office and his apartment without presenting a search warrant, he added.
Chane remains in detention at a crime investigation centre in the capital more than 48 hours after his arrest but has not yet been questioned or brought before a judge, Seyoum said.
The federal government had announced on August 9 that militia fighters had retreated from major cities in Amhara, but the violence is continuing in several areas.
On Sunday, Fano militants launched an attack on Gondar, the most populous city in Amhara and Ethiopia's former imperial capital, mostly targeting police, a security source and residents told AFP.
The federal army, which is in charge of security in Amhara under the state of emergency, said it had repelled the "attempted infiltration".
It is impossible to verify the situation on the ground in Amhara as media access to the region is heavily restricted.
Ezema was founded in 2019, a year after Abiy came to power, through the merger of several parties opposed to the EPRDF coalition that had ruled Ethiopia for several decades.
Ezema has four seats in the lower house of parliament that is dominated by Abiy's Prosperity Party, which he formed after dissolving the EPRDF.
One of Ezema's senior leaders, Berhanu Nega, serves in the federal government as education minister.