At least four soldiers were killed when an Israeli military helicopter crashed in Romania during a training exercise, the ministry of defence in Bucharest confirmed late Monday. Seven soldiers - six Israeli and one Romanian - were on board the helicopter when it came down in the Carpathian mountains, according to dpa. Four bodies have so far been recovered from the crash site, near the city of Brasov. The mountainous scene of the crash and heavy fog were making access difficult for rescuers. The CH-53 helicopter engaged in "Operation Blue Sky", a training exercise in search and rescue missions, likely crashed against a cliff, Mayor Gheorghe Hermeneaunu of the nearby village of Bran told the Mediafax news agency. The helicopter went down in flames and rescuers were using the smoke to orient themselves, he said. The defence ministry had not released a cause for the crash. Since 2000, Romania and Israel have had an agreement on military cooperation. Another agreement from 2006 has not yet been ratified by the Israelis.