New York - The Sudanese government is inflicting "irrevocable damage" in Darfur by expelling relief groups that provided humanitarian assistance to hundreds of thousands of people, UN Secretary General Ban Ki-moon said Thursday.

Khartoum has withdrawn work permits and expelled at least 13 non- governmental organizations involved in aid operations in Darfur since the International Criminal Court
(ICC) on Wednesday issued an international arrest warrant for Sudanese President Omar al-Bashir for alleged crimes against humanity and war crimes.

The UN said relief groups that operated in Darfur represented a lifeline to 4.7 million Sudanese people in Darfur.

Ban said in a statement that the relief groups had been working to meet the needs of Darfurians "in a neutral and impartial manner."

"As such, I appeal to the government of Sudan to urgently reconsider the above decision," Ban said in a statement.

"The secretary general is also concerned about the safety and security of national and international humanitarian workers in Sudan and their assets," the statement said. "The confiscation of equipment, money and other materials is unacceptable and must end immediately."

The groups expelled include the International Red Cross, Oxfam (Britain), Doctors Without Borders (France) and CARE (US). (dpa)