UN chief Ban Ki-moon expressed relief that four abducted South African peacekeepers serving with the UN-African Union mission (UNAMID) in Darfur have been released.

“The Secretary General is greatly relieved to learn about the release of the four peacekeepers who had been abducted in Darfur two weeks ago,” a UN statement said.

The four UNAMID police — two men and two women — who were abducted on April 11 as they left their team site just outside Nyala, were freed unharmed on Monday and are in good health, according to UNAMID spokesman Noureddine Mezni.

Ban expressed appreciation for Khartoum's efforts to secure their safe release and also thanked the South African government for its assistance.

The UN chief also emphasised to “all parties the importance of ensuring the safety of all UN and other personnel who are on the ground to help the people of Darfur."

The abduction of the four South African peacekeepers came as Sudan was holding its first multi-party elections since 1986, including in war-torn Darfur. The first full results were announced on Monday.

Sudan's President Omar al-Beshir, who is wanted by the International Criminal Court for crimes against humanity in the western region of Darfur, was declared the winner of the presidential contest.

The multi-party balloting — in which parliamentary and state representatives as well as a president were elected — were marred by complaints from the opposition and foreign poll monitors, as well as by accusations of fraud.

The United Nations says 300,000 people have been killed since the conflict in Darfur, pitting ethnic rebels against government troops and allied Arab militia, erupted in 2003.