BERLIN (Reuters) - There is no indication any outside forces were involved in the military helicopter crash in Mali in which two German peacekeepers were killed on a U.N. mission on Wednesday, a German military officer said.

“The reason for the crash is still completely open. There is no evidence at this point of any outside factors,” Vice Admiral Joachim Ruehle, deputy inspector general of the armed forces, told reporters.

German military investigators will head to the scene on Thursday to search for the helicopter’s flight data recorder, he said.

The Tiger helicopter crashed around 1220 GMT, about 70 km (45 miles) north of Gao, burning out completely with no survivors. The crash was reported by a second helicopter following in the mission.

All routine flights by other Tiger helicopters would be suspended indefinitely, he said. Only flights deemed necessary for “life and limb” would be conducted, with each decision to be made on a case-by-case basis.

“We have now certainty that two soldiers have given their lives in the service of our country,” German Defence Minister Ursula von der Leyen told a news conference in Berlin.