(Adds no immediate comment from Lukoil, details)
ACCRA, May 8 (Reuters) - A service helicopter carrying workers to an oil rig off the coast of Ghana operated by Russia's Lukoil crashed into the ocean on Thursday, killing at least three people, a military spokesman said.
Four people were rescued and another was missing, military spokesman Mbawine Attintande said. Lukoil did not immediately respond to an emailed request for comment.
The Ghana Civil Aviation Authority (GCAA) said the incident occurred after the helicopter, operated by Ghana's Volta River Aviation, took off from the western port of Takoradi on its way to the Jack Ryag oil rig near the giant Jubilee field.
The Air Force sent a helicopter at 2:38 p.m. (1438 GMT) to conduct a search after contact with the flight was lost, the GCAA added.
The cause of the crash was not immediately known. (Reporting by Kwasi Kpodo; Editing by Emma Farge and Robin Pomeroy)