A Canadian military helicopter serving with a NATO naval task force has gone missing in the Ionian Sea while participating in a mission in international waters off Greece.

Prime Minister Justin Trudeau confirmed the news in a tweet Wednesday evening. Trudeau said a search and rescue operation was underway and that other updates would be provided "as soon as possible."

Local media reports, quoting the Greek defence ministry, said the aircraft, with as many as six people aboard, had crashed into the sea.

A source with the Greek government told CBC News that one body had been recovered. Separately, local media in Greece also reported that wreckage had been spotted.

No one in the Canadian government would confirm the reports, nor offer comment. Officials contacted by CBC News late Wednesday said they expected that the prime minister would address the nation Thursday morning.

Little comment from NATO

A tweet from Canadian Armed Forces operations earlier Wednesday would only officially confirm there was an incident involving one of the air force's new CH-148 Cyclone helicopters.

"Contact was lost with the aircraft as it was participating in Allied exercises off the coast of Greece," the military said on Twitter and Facebook. "Search and rescue efforts are currently underway."

But in a tweet late Wednesday, the Canadian Armed Forces said it has contacted all primary family members of those who were on board the helicopter.

The CAF confirms we have contacted all primary family members of those who were on board the CH-148 Cyclone helicopter that was involved in an accident in the Mediterranean Sea. <a href="https://t.co/5wVjRjboCl">pic.twitter.com/5wVjRjboCl</a> —@CFOperations

A spokesperson for NATO provided little in the way of comment.

"I confirm there has been an incident involving a helicopter from a ship under NATO command," said Col. Juanita Chang, chief of public affairs at Supreme Headquarters Allied Powers Europe in Mons, Belgium.

"There is currently a search and rescue operation being conducted and national notifications taking place."

HMCS Fredericton is participating in NATO's Operation Reassurance and was carrying out operations in the Ionian Sea near Greece. (The Canadian Press)

Separately, a NATO source told CBC News that contact with the helicopter was lost early in the evening on Wednesday, around 8:15 p.m., local time. The flight was briefed as a routine flight operation while the task force was at sea, according to the official, who asked that their name be kept confidential because of the sensitivity of the subject.

NATO's Operation Reassurance

HMCS Fredericton is part of the standing NATO naval group currently in the area. It has been on deployment since January.

The Canadian Forces has confirmed contact was lost with a Canadian CH-148 Cyclone helicopter taking part in NATO operations in the Mediterranean. (CBC News)

The Greek state television channel ERT reported that the helicopter had come from the Canadian frigate, which is taking part in the alliance's Operation Reassurance meant to deter Russian aggression throughout Eastern Europe.

The crash reportedly happened late Wednesday in the Ionian Sea about 80 kilometres off the Greek resort island of Cephalonia.

HMCS Fredericton was reported to be part of the search operation, along with an Italian frigate and a Turkish frigate.

WATCH | Canadian military helicopter missing near Greece:

The Canadian Armed Forces says it lost contact with a helicopter off the coast of Greece amid reports of a crash. 2:39

The Cyclone is a militarized version of the Sikorsky S-92 utility helicopter.

It replaced the air force's five-decade-old CH-124 Sea Kings, which were gradually retired from service over the last few years. The crash of a Cyclone would represent a major blow given how long the military had to wait for the aircraft to be developed.

5 overseas missions to date

Originally ordered in 2004, the program faced delays and cost escalations to the point where former auditor general Sheila Fraser slammed the federal government's handling of the project in 2010.

The Cyclone routinely flies with a crew of four: two pilots, a tactical operator and a sensor operator. There is, however, room for several passengers. The helicopter's primary mission is hunting submarines, but it has a sophisticated surveillance suite and is also outfitted for search and rescue.

SNMG2 group assets ITS Fasan, HMCS Fredericton and TCG Salihreis train together with Italian frigates Alpino and Federico Martinengo near the Italian coast, April 17, 2020. (facebook.com/NATOMaritimeCommand)

Since coming into service, the Cyclone has been deployed on five overseas missions with the navy, including previous NATO stints.

The air force repeatedly has praised the aircraft's capabilities — although it was involved in at least one shipboard accident while serving with HMCS Regina and the resupply ship MV Asterix in the Pacific Ocean last year.

A Cyclone suffered what defence officials described at the time as a "hard landing" aboard the Asterix on Feb. 18, 2019.