European safety inspections of Yemenia aircraft revealed "significant findings" in the area of maintenance, the European Commission told the airline in a letter after one of its airliners crashed in the Indian Ocean.

The July 1 letter, obtained by Reuters, told Yemenia that if it did not provide assurances that it was taking "corrective action" on the deficiencies, it could be subject to an EU operating ban.

"Unless the Commission receives adequate evidence with respect to the requested information, it will be obliged to propose to subject all operations of Yemenia Yemen Airways into the Community to an operating ban," it said.