U.N. Secretary General Ban Ki-moon. Pic: AP.

UNITED NATIONS (AP) — Secretary-General Ban Ki-moon is urging Burma’s government to ensure the safety of U.N. and international aid workers following attacks in troubled Rakhine state.

Ban’s spokesman said Monday the U.N. chief spoke to President Thein Sein on Sunday after Buddhist mobs attacked offices and homes of aid workers, forcing them to relocate.

Rohingya Muslims in the western state of Rakhine have been the targets of Buddhist mob attack in the last two years.

The spokesman said Ban stressed that impunity cannot be tolerated in the context of Burma’s reform process.

Burma began a census Sunday that has been criticized for stoking religious and ethnic tensions, after the government denied members the Muslim minority the right to identify themselves as “Rohingya.”

The secretary-general underlined that the census must be peaceful and credible.