TPLF on Monday said Tigrayan forces controlled Korem, a town 170 kilometres (105 miles) south of the capital Mekelle.
Ethiopia’s Prime Minister Abiy Ahmed has pledged to repel attacks by the country’s “enemies” after rebels in Tigray launched a fresh offensive to regain territory in the war-torn region.
Tigrayan forces this week claimed a series of battlefield gains in a renewed assault that comes two weeks after the federal government declared a unilateral ceasefire in the face of rebel advances.
The latest rebel push followed the stunning recapture of the regional capital, Mekelle, 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.
On Wednesday, 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.
“We’ve undertaken a unilateral ceasefire to avoid further conflict, to provide the people with a reprieve during the farming season, and to allow aid operations to proceed without excuse,” he said.
“Even though we knew peace would exact some cost on us, we have taken the peaceful option.”
But he said Ethiopia’s enemies were “unable to rest without conflict” and accused them of using child soldiers.
He urged Ethiopians to remain united and stand behind the Ethiopian army and resist “outside pressure and internal provocation”.
The ruling party won the recently concluded parliamentary elections in a landslide boosting Abiy’s power in the country marred by conflict.
A spokesman for the Tigray Defence Forces (TDF) told the AFP news agency on Tuesday they had seized Alamata, the main town in southern Tigray, and pushed into the western part of the region where fertile farmlands have long been contested. The region’s main party, Tigrayan People’s Liberation Front (TPLF), have recently been rebranded as the Tigray Defence Forces (TDF).
The rebel claims could not be independently confirmed as communications were largely down in the area, but United Nations and humanitarian sources reported fighting around towns in western Tigray and in a refugee camp.
Abiy and Ethiopian officials characterised their troop withdrawal from Mekelle as a strategic move while the TDF described it as a major rebel victory, and the declaration of a ceasefire a “joke”.
However, they later accepted it “in principle” while demanding the withdrawal from the region of forces from neighbouring Eritrea and the Amhara region of Ethiopia.
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.
The World Food Programme said this week that it had reached Mekelle with food supplies but far more was needed to address the massive need in a region where the United Nations says famine conditions are already present.