A Cypriot airliner with 121 people on board from Larnaca, Cyprus, crashed on Sunday on a mountain on the Euboea peninsula, northeast of Athens, a traffic controller at Athens international airport said.
Just before the crash, an airport official said the plane appeared to be flying pilotless.
"The airport lost all contact with the plane, which should have landed in the late morning, and two air force planes sent up in reconaissance found it flying above the Euboea peninsula, but they saw the pilots doubled up in the cabin," Iannis Pantazaratos, traffic control chief at Athens airport, said.
"We do not know how the plane is flying. It is being escorted by the military planes and the airport is in a state of emergency," said Pantazaratos.
The Helios airlines plane was reported to be carrying 115 passengers and six crew.
"The information was given to us by the air force, which sent two fighters to escort the aircraft," said Pantazaratos.
Helios, established in 1999, is the first private airline in Cyprus. It had a fleet of four Boeing 737 jets and operated flights to London, Athens, Sofia, Dublin and Strasbourg in France.