The crew of the Ethiopian Airlines plane that crashed last month killing 157 people, repeatedly followed procedures recommended by Boeing, but were unable to regain control of the jet, according the investigators' report released on Thursday.

The initial report, unveiled by Ethiopian Transport Minister Dagmawit Moges, cast further doubt on the system controlling the Boeing 737 MAX 8 model, which has been grounded worldwide for almost a month. "The crew performed all the procedures repeatedly provided by the manufacturer, but was not able to control the aircraft," said Dagmawit Moges. "Aviation authorities shall verify that the review of the aircraft flight control system has been adequately addressed by the manufacturer before the release of the aircraft for operations," she added. Boeing is reviewing the report.