Brussels  - The European Commission said Monday it was probing concerns that the planned acquisition by Dutch airline KLM of Martinair could leave passengers wishing to travel from Amsterdam to the Caribbean islands of Curacao and Aruba with less choice.

"The commission's initial market investigation indicated that the proposed acquisition might substantially reduce competition, and so raise serious doubts as to its compatibility with the (EU's) single market," the European Union executive said in a statement.

Officials in Brussels said they had decided to open an in-depth investigation after remedies proposed by KLM had failed to remove the EU's serious doubts" about the takeover.

"At a time of consolidation in the European airline sector, the commission must make sure that consumers continue to have a competitive choice of airline services," said Competition Commissioner Neelie Kroes.

The commission now has 90 working days to reach a decision on the case. (dpa)