Fighting erupted Tuesday between rival forces in a refugee camp in Ethiopia's war-hit Tigray, after local rebels launched a new offensive to reclaim towns and territory in the region.
A spokesman for the Tigrayan forces told AFP they had seized Alamata, the main town in southern Tigray, in a fresh assault two weeks after the federal government declared a unilateral ceasefire in the face of rebel advances.
Getachew Reda said fighting was also taking place in western Tigray, an area where the United States has raised concerns about ethnic cleansing, and where clashes inside a refugee camp on Tuesday sent people fleeing.
The rebel claims could not be independently confirmed as communications were largely down in the area. An Ethiopian military spokesman did not immediately respond to a request for comment.
The Tigray Defence Forces (TDF) last month swept across parts of Tigray and seized its capital Mekele, a turning point in the brutal eight-month conflict with federal troops.
The fighting -- marked by massacres and sexual violence -- has killed thousands, while the UN says hundreds of thousands face famine.
Security forces and officials from neighbouring Amhara region had moved in to southern and western Tigray in November to support the Ethiopian army after Tigrayan forces cleared out during the war's early phase.
"We promised to liberate every square inch of Tigray," Getachew said, announcing the new offensive launched Monday.
The TDF fighters "were able to absolutely rout federal defence forces and Amhara special forces divisions", he said, claiming they had taken most of southern Tigray including Alamata.
Getachew said the TDF was "in hot pursuit" of pro-government forces, adding: "We don't want to give them a chance to regroup."
A UN source reported the sound of artillery near the western Tigray town of Emba Madre and fighting around Mai Tsebri, 13 kilometres (eight miles) away.
Humanitarian sources told AFP fighting also broke out inside the nearby Mai Aini camp housing Eritrean refugees, with Tigrayan rebels exchanging fire with Ethiopian soldiers and their allies in Amharan special forces.
"There was fighting inside the camp," one source said. "Some refugees have started walking from the camps south."
By midday the fighting seemed to have subsided, with Tigrayan forces controlling much of the area, the source said. There was no immediate word on casualties.
Two camps for Eritrean refugees located further north, near the border with Eritrea, were destroyed earlier in the war.
A local government office in the Amhara region to the south of Tigray had called Monday for a "mass mobilisation" of people with arms and food to Mai Tsebri.
The rebel offensive was launched two days after results showed Prime Minister Abiy Ahmed won by a landslide in June elections that went ahead despite the conflict.
The TDF had described its seizure of Mekele and most of Tigray as a major victory and initially branded the government's unilateral ceasefire a "joke."
Rebel leaders later said they accepted the ceasefire "in principle" but posed strict conditions including the withdrawal from the region of Eritrean and Amhara forces.
Abiy and other officials have said federal forces executed a strategic pullback to focus on other threats.
Abiy -- who won the Nobel Peace Prize in 2019 for his peace deal with neighbouring Eritrea -- sent troops into Tigray last November to oust the region's once-dominant ruling party, the Tigray People's Liberation Front (TPLF).
Abiy accused them of orchestrating attacks on Ethiopian military bases in Tigray, an important economic and industrial region.
The war has badly damaged Abiy's international standing, and Western powers have demanded the ceasefire be accompanied by unfettered aid access.
EU foreign policy chief Josep Borrell on Monday urged member states to consider sanctions, warning that a major humanitarian disaster loomed.
The World Food Programme (WFP) said Monday that a 50-truck convoy carrying 900 tonnes of supplies had arrived in Mekele but was far from enough to help the hunger-stricken region.
"We need double this number of trucks arriving daily, and we need them to take two days to reach Mekele instead of the four-day journey this time if we are to reach the millions of people in need of life-saving assistance," said WFP emergency coordinator Tommy Thompson.
The US, a traditional ally of Ethiopia, reiterated Monday its finding that "acts of ethnic cleansing" had taken place in western Tigray, and warned that any effort to redraw internal boundaries by force was "unacceptable".
"Any issue of such national importance, like borders, would be an issue for the Ethiopian people to decide through consensual dialogue, not through the barrel of a gun," said State Department spokesman Ned Price.
Tigrayan officials in March accused Amharan forces of expelling thousands of people from land in western Tigray -- a part of the region that ethnic Amharas claim rightfully belongs to them.
Many ethnic Amharas believe the once-dominant TPLF illegally incorporated the fertile territories after it came to power in the early 1990s -- and that they should fall under Amhara administration.