Foreign Secretary Philip Hammond has offered his condolences to the family of four Britons killed when a seaplane crashed during a sightseeing trip in Canada.
The victims have not yet been named following the crash, on Sunday afternoon in the Les Bergeronnes area of Quebec province.
Canadian authorities tonight warned it could take some time before the cause of the crash is known.
Mr Hammond said tonight: "This terrible incident has taken the lives of all on board, including four British nationals. My thoughts and sympathy are with their family and friends at this difficult time.
"Our High Commission in Ottawa is in close contact with the Canadian authorities and we are providing consular assistance to the relatives of those who were killed."
Five passengers and a pilot were killed when the Beaver aircraft they were in came down in woodland.
A picture on the Transportation Safety Board of Canada's website shows the wreckage of the red and white aircraft on a rock edge next to thick woodland.
The plane, operated by Air Saguenay, took off from Lac Long in Tadoussac on a routine sightseeing flight before crashing on Sunday afternoon.
An Air Saguenay official said the flight was supposed to last 20 minutes and flying conditions at the time were "excellent".
Le Journal de Quebec reported that the plane crashed into a mountainside 20km (12 miles) from Tadoussac where the tourists were staying, and the impact was so violent nobody could have survived.
The newspaper named the pilot as Romain Desrosiers and one of the passengers as Emilie Delaitre, a French woman from the Cote d'Azur.
The crash site was located by Canadian forces who flew over the search area.
Although the weather was good when the flight took place, cloud and rain significantly affected efforts to access the steep and densely wooded area.
Police said the bodies of all six people had been found, while investigators from the Transportation Safety Board of Canada were sent to the scene.
The bodies were moved to a laboratory today for forensic tests.
Jean-Marc Ledoux, a regional manager with the Transportation Safety Board of Canada, said it would take time before the cause of the crash is known.
He said: "We're taking the time to conduct a thorough investigation, and because it was a smaller plane there was no flight data record, which will obviously make matters more difficult.
"There will always be different factors that contribute to these incidents.
"It is always hard to say how long these investigations will take."
He was unable to confirm the identity of those on board as victims' next of kin may not have been contacted.