Ethiopia's human rights watchdog on Tuesday urged authorities to "bring credible charges or release" four media workers arrested in the country's conflict-hit northern Tigray region.
Daniel Bekele, head of the Ethiopian Human Rights Commission (EHRC), said in a Twitter post he was "concerned" about the arrests, the first of which occurred Saturday.
"While misinformation & disinformation are recurring challenges in the crisis, arresting journalists is disproportionate response. Bring credible charges or release," the post said.
The EHRC is a government-affiliated but independent body.
The arrested media workers include Fitsum Berhane and Alula Akalu, who were working as translators for journalists from Agence France-Presse (AFP) and the Financial Times.
Both outlets had obtained permission from the Ethiopian Broadcasting Authority and the Ministry of Peace to work in Tigray, where media access has been tightly restricted since hostilities began five months ago.
Ethiopian officials have not said why they were arrested or what they are being investigated for.
AFP's global news director Phil Chetwynd called Monday for Fitsum's immediate release.
"We have not been informed of any specific charges against Fitsum Berhane. His collaboration with a media outlet should not be a motive for his arrest," he said.
The other arrested media workers are BBC journalist Girmay Gebru and Temrat Yemane, a local journalist.
Soldiers carried out all the arrests, according to the men's relatives and witnesses.
Prime Minister Abiy Ahmed announced military operations in early November against leaders of Tigray's ruling party, the Tigray People's Liberation Front (TPLF), saying they came in response to attacks orchestrated by the party on federal army camps.
He said hostilities were "completed" in late November when federal forces entered Mekele, the regional capital, but TPLF leaders remain on the run and fighting has continued.
Reports of atrocities against civilians continue to mount, including by soldiers from neighbouring Eritrea which has teamed up with Abiy against the TPLF.
Both Addis Ababa and Asmara officially deny Eritrean troops are active in the region, despite widespread reports of their presence.
The Foreign Correspondents' Association of East Africa on Tuesday called for the immediate release of journalists detained in Tigray.
"Targeting journalists and their associates... gravely undermines the government's promise to open up to the press," the groups said in a statement.