Four Britons died when a seaplane crashed during a sightseeing trip in Canada, according to reports.
The Foreign Office is "urgently working" with Canadian authorities to establish whether Britons were among the six people who died in the crash.
Five passengers and a pilot were killed when the Beaver seaplane they were travelling in crashed in woodland in the Les Bergeronnes area, in the Quebec province.
A picture on the Transportation Safety Board of Canada's website shows the red and white aircraft crashed into 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 told AP 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 newspaper said the four other passengers were British and may have rented a car with an Ontario number plate to drive to the Cote-Nord region.
There were conflicting reports about whether the plane had made a distress call prior to the crash.
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 are expected to be moved today and taken to Montreal for forensic tests.
Le Soleil reported the tourists bought tickets through Aviation du Fjord which had worked with Air Saguenay for three years.
The seaplane was reportedly a De Havilland DHC-2 Beaver, built between 1950-1960, which was being flown by an experienced pilot who had worked for Air Saguenay for more than a decade. The firm said the aircraft was well maintained.
A spokesman for the Foreign Office said: "Following a plane crash in Les Bergeronnes, Canada, we are urgently working with local authorities to establish the identity of those on board."
According to reports, Air Saguenay upgraded its security system after the same kind of seaplane, a De Havilland DHC-2 Beaver, crashed into a mountain in bad weather killing four of the six people on board.
An investigation by the Transportation Safety Board of Canada into the 2010 tragedy found that poor weather conditions hampered visibility and was responsible for the crash.
It also concluded that a lack of training on pilot decision-making for air taxi operators "exposes pilots and passengers to increased risk when flying in adverse weather conditions".
The inquiry also found that it took the company's main operating base at Lac Sebastien three hours and 40 minutes to alert the Joint Rescue Co-ordination Centre to the fact the plane had been delayed, whereas they should have been notified after just an hour.
This delayed search and rescue efforts.