The head of the United Nations High Commission for Refugees (UNHCR) expressed deep concern Monday over the plight of North Korean defectors in China and their unprotected human rights.

During the agency's annual executive committee meeting, Ruud Lubbers, the U.N. High Commissioner for Human Rights, said North Koreans who flee from their country "may well be considered refugees" and that their human rights situation should be considered by the UNHCR.

China, an ally of the North, refuses to recognize the fleeing North Koreans as refugees, labelling them "economic migrants" seeking jobs in the country. China is obliged by a treaty with Pyongyang to repatriate northern defectors.

There is no official data on the exact number of North Korean asylum-seekers, but the UNHCR believes that as many as 300,000 North Korean residents have fled to northeastern China.

Lubbers said the defectors should not be forced to go back home, where they would reportedly face persecution.

His remarks came amid US pressure on the United Nations to more actively address the growing number of North Koreans residing illegally in China.