As fighting continues in and around the Libyan capital of Tripoli, more than 140,000 refugees are reportedly trying to leave the country, and aid workers are struggling to provide them with basic shelter and necessities.

“We can see acres of people waiting to cross the border,” said a U.N. official at the Tunisian border town of Ra’s Ajdir.

“Many have been waiting for three to four days in the freezing cold, with no shelter or food,” said Ayman Gharaibeh, the head of the emergency response team from the office of the U.N. High Commissioner for Refugees.

Tuesday, the U.N. commissioner himself, Antonio Guterres, called for a “massive evacuation” of refugees who have crossed from Libya into Tunisia, saying that the fragile country cannot cope with the thousands of Egyptians who have made it into Tunisia.

Guterres told the BBC’s Imogen Foulkes that without help, the situation could turn into a “huge humanitarian disaster.”

That warning came a day after Guterres told Reuters that he believed some of the refugees ran the risk of facing even more abuse as they tried to leave Libya.

“Africans seem to be particularly at risk, as they are being associated with foreign mercenaries,” he said.

An AP report from Libya depicts refugees’ desperation to escape — and the efforts by Moammar Gadhafi’s government to stop them:

Officials say the situation has been made even more volatile by humanitarian aid workers being blocked from reaching western Libya, patients reportedly being executed in hospitals — or shot by gunmen hiding in ambulances.

At the Libya-Tunisian border, where authorities say up to 75,000 people have gathered in just nine days, “The situation is reaching crisis point,” U.N. refugee agency spokeswoman Melissa Fleming warned.

According to Fleming, some 14,000 people fled from Libya to Tunisia Monday, and another 15,000 were expected to try to leave Tuesday.

The violence and human rights abuses that many refugees say they are fleeing led the U.N. General Assembly to suspend Libya from the Human Rights Council today. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.