ATHENS (AFP) - Two planes were forced to circle over a Greek island awaiting permission to land on Monday after an air traffic controller overslept and was late for work, Greece's civil aviation authority said.

The Transport Ministry launch a probe into the incident at the airport in the island of Lesbos that delayed a domestic flight from Athens and a charter from Slovakia, the YPA aviation agency said.

The air traffic controller told his bosses that his mobile phone alarm had broken down, causing his tardiness, according to Greece's Net television.

While the planes circled over the island, the airport director called one the controller's colleagues. After waiting 30 minutes, the two aircraft landed safely, YPA said.

The European Commission told Greece in September to improve its oversight of airport safety to conform with EU rules or face action before the European Court of Justice.