NEW YORK — The United Nations said South Sudan’s armed forces shot down a UN helicopter on Friday, killing all four Russian crew members on board — but South Sudan’s military spokesman blamed rebel fighters.
Secretary-General Ban Ki-moon stood by the UN’s account in a statement, strongly condemning the shooting down ‘‘of a clearly marked UN helicopter by the Sudan People’s Liberation Army’’ and calling on South Sudan’s government to conduct an immediate investigation and prosecute those responsible.
Ban sent condolences to the families of the four crew members, whose names were not released, and to the Russian government.
Earlier, UN deputy spokesman Eduardo del Buey said the helicopter from the UN peacekeeping mission in South Sudan was on a reconnaissance mission when it was shot down. The mission, known as UNMISS, said the helicopter was not carrying any passengers.
‘‘In subsequent communications between the mission and the South Sudanese Armed Forces, the SPLA told the mission that it has shot down the helicopter in the Likuangole area in Jonglei state,’’ del Buey said.
Pibor County in Jonglei state, where the helicopter was shot down, has been the scene of recent clashes between rebel militia fighters led by David Yauyau and South Sudanese forces. A former member of the South Sudanese Army, Yauyau launched his rebellion after failing to win a parliamentary seat in the Sudanese general elections in April 2010. South Sudan accuses Sudan of arming Yauyau.
South Sudan military spokesman Kella Kueth denied that his military shot down the UN helicopter: ‘‘It was the forces of Yauyau. Yauyau’s forces are working with Khartoum for the downfall of South Sudan.’’
Earlier, SPLA spokesman Philip Aguer said that ‘‘the helicopter crashed somewhere between the SPLA base and the Yauyau base in the Pibor area.’’
He said he didn’t know what caused the crash.
‘‘I think the government of South Sudan and UNMISS need to investigate this jointly,’’ Aguer said.
South Sudan Information Minister Barnaba Marial Benjamin said that the cause of the crash is not known.