NAIROBI, Kenya (AP) — Ethiopia's announcement that it has completed its military offensive in its defiant Tigray region “does not mean the conflict is finished,” the U.N. refugee chief said Sunday, adding he is very concerned about the fate of nearly 100,000 Eritrean refugees there amid reports that some have been abducted.

If confirmed, such treatment of refugees in camps close to the Tigray border with Eritrea “would be major violations of international norms,” Filippo Grandi told reporters. “It is my strong appeal for the prime minister of Ethiopia for this situation to be addressed as a matter of urgency.”

Nearly a month of fighting between Ethiopian federal forces and Tigray regional ones has threatened to destabilize Ethiopia, the linchpin of the strategic Horn of Africa, and its neighbors. The involvement of Eritrea in the conflict has been alleged by refugees and the now-fugitive Tigray leaders but, like much in the sealed-off region, has not been verified.

Meanwhile, in a rare report from inside the Tigray capital of Mekele, the International Committee of the Red Cross said a major hospital in northern Ethiopia, Ayder Referral Hospital, is lacking body bags while some 80% of its patients have trauma injuries.

“The influx of wounded forced the hospital to suspend many other medical services so that limited staff and resources could be devoted to emergency medical care,” it said.

Hospitals and health centers in the Tigray region are running “dangerously low” on supplies to care for the wounded, it added. Food is also running low, the result of the Tigray region being cut off from outside aid for almost a month.

The ICRC also said 1,000 Eritrean refugees have arrived in Mekele from their refugee camps near the Eritrean border, looking for food and other help.

Eritrea, which watchdogs call one of the world's most repressive countries, has remained almost silent on the allegations by the Tigray regional leaders that it has been involved in the conflict at the invitation of Ethiopia and its Nobel Peace Prize-winning Prime Minister Abiy Ahmed, whose government has denied it.

Overnight, the U.S. Embassy in Eritrea said six explosions were heard in the capital, Asmara. It followed an embassy report of another “loud noise, possibly an explosion” on Friday, nearly two weeks after the Tigray regional leader confirmed firing missiles at the city.

The latest explosions came just hours after Abiy declared victory in his government’s fighting against the Tigray People’s Liberation Front, which has run the northern Tigray region. The army said it was in “full control” of Mekele but the government said TPLF leaders remain on the run.

The U.S. has accused the TPLF of seeking to “internationalize” the deadly conflict in which aid groups say several hundred people have been killed, including civilians.

Communications remain almost completely severed with the Tigray region of 6 million people, and the U.N. has been unable to access it with aid. Fears are growing about the atrocities that might emerge once transport and other links are restored.

It has been impossible to verify claims made by the warring sides.

Nearly 1 million people have been displaced, including about 44,000 who fled into Sudan. The camps that are home to the 96,000 Eritrean refugees have been in the line of fire.

“We need first and foremost access” to Tigray, Grandi said, adding that his U.N. colleagues in Addis Ababa are in discussions with the government there. Abiy's government has promised a “humanitarian corridor" managed by itself, but the U.N. has stressed the importance of neutrality.

Asked about refugees' allegations that Ethiopian security forces have blocked people from fleeing the conflict into Sudan, the U.N. refugee chief said his team had not raised that issue with Ethiopia's government. But refugees told him about the “many checkpoints” and pockets of insecurity they faced as they fled.

“We have not heard of any systematic sealing-off,” Grandi said. “But certainly there are growing difficulties."

Most people traveled with nothing, Grandi said, and many are farmers who were forced to flee at harvest time, creating a “very difficult situation for them.”

Even before it declared victory in the conflict, Abiy's government was urging the refugees to return and promised to protect them. But many of the refugees have said they were running from the deadly violence of Ethiopian forces and attacks from the direction of nearby Eritrea.

“Of course, I'm not encouraging people to return,” Grandu said, adding that refugees told him they fear possible retaliation and intercommunal violence and need security assurances before they can go home.

The U.N, refugee agency is asking for almost $150 million in aid over the next six months to support up to 100,000 refugees.