Ethiopia arrests hundreds for 'support of Tigray rebels'
Addis Ababa Police Commissioner, Getu Argaw, said those detained had suspected links to the Tigray People's Liberation Front (TPLF), the region's once-powerful ruling party the government has since outlawed as a terrorist group.
"323 people suspected of helping the TPLF in various activities have been arrested," Getu told the Ethiopian Broadcasting Corporation.
"Businesses that are alleged to have links to the suspects have been shuttered and are currently under investigation."
Some were also being investigated for allegedly possessing weapons, smoking hash, gambling, and insulting the national flag and constitution, he said.
The arrests comes as the war in Tigray takes on a new dimension, with the deployment of forces from several regions in the fight against the Tigrayan rebels signalling a potential widening of the conflict.
The fighting has already left thousands dead and, according to the United Nations, pushed 400,000 into famine.
Amnesty International on Friday accused Ethiopia of arbitrarily arresting dozens of ethnic Tigrayans in Addis Ababa and elsewhere since rebels retook control of the region's capital last month.
Those detained have included activists and journalists, and some have been beaten and transported hundreds of kilometres (miles) from the capital, Amnesty said.
The total number is likely to be in the hundreds, with the whereabouts of many unknown, Amnesty said.
Abiy's government has previously denied engaging in ethnically-motivated arrests
The Ethiopian Human Rights Commission (EHRC), a state-affiliated but independent body, said it was also monitoring reports of arbitrary arrests, business closures and "other types of harassment targeting ethnic Tigrayans".
The EHRC and rights groups have similarly voiced concern about previous rounds of such arrests going back to the beginning of the war.
The latest rebel push followed the stunning recapture of the regional capital Mekele last month from federal forces, a turning point in a brutal eight-month conflict that has killed thousands of people and left many hundreds of thousands facing famine.
Abiy said he remained committed to peace - even if it came at a "cost" - but these latest attacks would not go unanswered.
"We will defend and repel these attacks by our internal and external enemies, while working to speed up humanitarian efforts," he said in a statement posted on Twitter.
Abiy, the winner of the Nobel Peace Prize, sent troops into Tigray last November after accusing the region's once-dominant ruling party of orchestrating attacks on Ethiopian military bases.
He said Ethiopia had demonstrated its willingness to end hostilities in the mountainous northern region.
The war, characterised by grisly massacres and rampant sexual violence, has damaged Abiy's standing as a reformer and peacemaker, and badly strained Ethiopia's ties with traditional allies.
Western powers have demanded the ceasefire be accompanied by unfettered aid access and the withdrawal of Eritrean troops, warning of possible sanctions should these conditions not be met.