The missing helicopter had taken off from the Canadian frigate Fredericton for a patrol. (Photo: AFP)

Debris from a Canadian military helicopter that went missing during a NATO operation has been found in the sea between Greece and Italy, a Greek military officer and public television said Thursday.

NATO said the Cyclone Sikorsky CH-148 helicopter crashed after taking off from the Canadian frigate Fredericton on Wednesday.

"Debris has been found in Italy's zone of control and intervention" in the Ionian Sea, the Greek military officer told AFP, specifying the wreckage belonged to the Canadian helicopter.

Six crew were aboard the helicopter when it disappeared, the officer said on condition of anonymity.

NATO declined to give details, noting that information "will be released in accordance with national procedures".

The Canadian Armed Forces (CAF) have not said so far how many personnel were on board.

Greek public television earlier reported that a body had been found amid the wreckage in international waters off the Greek island of Kefalonia.

But the Greek military officer did not immediately confirm a body had been found.

CAF have not confirmed that any debris has been found, but said on Twitter it contacted the family members of those who were on board the missing helicopter.

The aircraft was "involved in an accident in the Mediterranean Sea", it said, but gave no other details.

CAF issued a statement earlier saying it had lost contact with the helicopter deployed on board HMCS Fredericton, which was participating in NATO exercises off the coast of Greece.

Allies join search 

"Search and rescue efforts are currently under way," it added.

Juanita Chang, spokeswoman for Supreme Headquarters Allied Powers Europe (SHAPE), said NATO ships and air assets were taking part in the search, supported by maritime and air components from Greece, Italy, Turkey and the United States.

Initial reports said the helicopter had been over international waters 50 nautical miles (93 kilometers) off Kefalonia.

Italian, Greek and Turkish frigates were taking part in the exercises along with the Canadians.

Chang said the Fredericton was part of NATO's Standing Maritime Group Two and had recently sailed from the base of Souda on Crete on a mission of "maritime situational awareness in the Mediterranean".

The group "performed several exercises with units of the Turkish navy followed with exercises with the (Greek) navy and airforce this past week", Chang said.