About 1,000 people left the Awlala settlement in Amhara on May 1 over fears for their safety after reports of armed robbery, shootings and alleged abductions, and some have begun a hunger strike, the UN refugee agency (UNHCR) said Tuesday.
"While we fully understand their legitimate request for better security and services, we are concerned that their protest along the road, their stay in unsanitary conditions, and the hunger strike initiated by some risk further increasing their vulnerability," it added.
Awlala and another nearby camp called Kumer are about 70 kilometers (40 miles) from the Metema border crossing into Sudan, which descended into a brutal conflict between rival generals in April last year.
"The security environment on the ground remains deeply challenging, including for our own teams and humanitarian workers," the UNHCR said, noting the killing of an aid worker in Amhara on Friday.
Medical Teams International, a US-based charity, confirmed this week that one of its staff members was killed and others wounded when their convoy was fired upon by armed men.
Fighting erupted last year between federal Ethiopian forces and an armed militia in Amhara, leading the government in August to impose a state of emergency that remains in place to this day.
The UNHCR said that water, health care and other services were still available at Awlala for the stranded refugees and that it was continuing to encourage the group to return to the site.
As of the end of April, the Kumer camp hosted about 6,000 people, mainly from Sudan, Eritrea and South Sudan, while about 2,000 were at Awlala, mainly Sudanese and South Sudanese refugees, it said.
Ethiopia now hosts a total of more than one million refugees, making it the second-largest refugee hosting country in Africa after Uganda, the agency said.
An estimated 1.8 million people have fled Sudan since the war began, out of a total of about 8.8 million people displaced, according to UN figures.