GENEVA (AP) — It will be difficult to improve the safety and living conditions of tens of thousands of Congolese refugees who have fled into Uganda following rebel attacks. U.N. officials said Tuesday.

As many as 70,000 Congolese have fled into western Uganda because of attacks by a Ugandan-led rebel group and continued clashes with Congolese army forces, said Patrick McCormick, a spokesman for UNICEF, the U.N. children's agency.

Even before the recent influx to a transit center outside the Ugandan town of Bundibugyo, he said, Uganda already was hosting more than 210,000 registered refugees and asylum seekers, nearly two-thirds of whom come from Congo.

Adrian Edwards, spokesman for the U.N. refugee agency, said the Uganda Red Cross had registered more than 66,000 Congolese refugees as of Sunday night, but substantially more have arrived since then.

"Moving the refugees to safer areas is now a major challenge," Edwards told reporters in Geneva. "We are worried about their current situation, as the conditions that many are living in are dire."

The refugees are dotted across an exposed, hilly area that's extremely cold at night, is short of drinking water and food, and is almost completely lacking in sanitation, he said.

He said government and U.N. forces are responsible for the safety of the refugees.

The region has been wracked by brutal violence, including the use of rape as a weapon of war, since Rwanda's 1994 genocide spilled conflict across the border.

On Monday, the U.N. mission in Congo said it is ready to use lethal force to protect civilians.