Two Russian contractors working for the United Nations have been kidnapped in Sudan's Darfur region and hostage takers have allegedly demanded ransom for their release, media reports said. The men were reportedly working for UTair, an airline company contracted by the UN peacekeeping mission in Darfur (UNAMID), western Sudan.

Artur Safukov, spokesperson for the Russian embassy in Khartoum, Sudan, said on Tuesday that efforts were being made to secure the pair’s release, Agence France Press reported. Safukov had said earlier on Monday that the duo had been taken hostage on Jan. 29, according to Sputnik News, Russia’s official news agency.

“The kidnappers told UNAMID that they await ransom for the release of their employees. UNAMID workers have been kidnapped in Darfur several times, and the government has warned against paying ransom to avoid the recurrence of such incidents,” Sputnik News reported, citing a source.

UTair said, according to Reuters, that its employees had been kidnapped from the town of Zalingei in Darfur province. However, the company, which operates domestic and international passenger flights, helicopter services and charter flights, reportedly said that the hostage takers have not made any demands yet.

"A UNAMID minibus was blocked by six cars. The passengers were forced to get off the minibus at gunpoint and led off in an unknown direction," the company said, in a statement, according to Reuters.

In August last year, a United Nations helicopter, which was on a routine cargo flight in South Sudan, crashed and killed three of its four Russian crew members. Rebel groups in the region had claimed responsibility for the attack and said that fighters loyal to former South Sudan Vice President Riek Machar had shot down the plane.