Under-Secretary-General of the Department of Field Support, Susana Malcorra stated Tuesday that Russia is considering withdrawing its military helicopters servicing the U.N. peacekeeping force in South Sudan after voicing alarm over attacks on Russian personnel there. "My sense is that at this point in time, Russia is seriously considering whether to stay or to leave South Sudan," Malcorra said, adding that the departure of Russia, which provides key services for the U.N. Mission in South Sudan (UNMISS ) could complicate matters in Africa's newest country. Malcorra said in a published interview “until recently, Russia had eight helicopters that were being used by UNMISS, after its utility helicopters were attacked by South Sudanese security forces last autumn, Russia decided in December to withdraw four of them and now appears to be contemplating the withdrawal of the other four.” "It is clear that the reason why Russia has (grounded) the helicopters is based on the threat and the risk the troops have faced," she said. "And I can fully understand that." South Sudan's government has apologized to Russia for the attacks on its helicopters last year and vowed to take steps to ensure there were no new attacks on Russian aircraft by South Sudanese. In August 2010, the Russian crew of a Mi-8 helicopter owned by the Sudanese Airways was detained over its suspected ties with the rebels. The pilots were held in Juba for about two months before finally being released in October the same year. Meanwhile, it was reported that another Russian pilot has been detained in South Sudan. He was employed by the local Park Air airline. On December 28, he and the other crewmembers of an AN-32 aircraft were arrested at a local airport shortly before takeoff and placed into a special military camp. The crew also comprises citizens of Ukraine, Uzbekistan, Armenia and Sudan. For his part, Sudan People's Liberation Army (SPLA) spokesperson Colonel Philip Aguer denied any attacks against Russians in (UNMISS ), stressing that it happened only once, last year and South Sudan's government has apologized to Russia.