A team of US federal air accident investigators was expected to arrive in Alaska to seek the cause of a midair collision between two sightseeing planes that killed at least four people.
The four died when the seaplanes carrying cruise ship tourists collided on Monday near the southeast Alaska town of Ketchikan, the Coast Guard said.
Two others were missing, said Petty Officer Jon-Paul Rios, a Coast Guard spokesman.
Canadian officials said a Canadian was among the dead.
Global Affairs Canada expressed condolences but did not identify the person because of privacy reasons, the government department said in a statement.
The Washington, DC-based investigative team from the National Transportation Safety Board was expected to arrive in Ketchikan, agency spokesman Peter Knudson said.
He said board member Jennifer Homendy also is travelling with the so-called Go Team, which investigates major accidents.
The floatplanes collided under unknown circumstances, Federal Aviation Administration spokesman Allen Kenitzer said.
Floatplanes have pontoons mounted under their fuselages so they can land on water.
The passengers from the cruise ship Royal Princess were on sightseeing flights, one operated by Ketchikan-based Taquan Air.
Eleven people were in Taquan’s single-engine de Havilland Otter DHC-3 when it went down during its return from a trip to Misty Fjords National Monument, which is part of the Tongass National Forest, the nation’s largest.
Ten people were taken to a Ketchikan hospital.
All patients were in fair or good condition, according to Marty West, a spokeswoman for PeaceHealth Ketchikan Medical Centre.
Three of those who died were among five people aboard the second plane, a single-engine de Havilland DHC-2 Beaver, according to Coast Guard Lieutenant Brian Dykens.
It was unclear which plane carried the fourth victim, whose body was recovered during a Monday night search, Rios said.
Local emergency personnel worked with state and federal agencies and private vessels to help rescue and recover victims.
“It’s been a long day and the crews have been working really hard to rescue people and recover the deceased,” said Deanna Thomas, a spokeswoman for the Ketchikan Gateway Borough the local government.
Taquan Air said the company suspended operations while the crash is investigated.
“We are devastated by today’s incident and our hearts go out to our passengers and their families,” Taquan said in a statement.
The cruise ship left Vancouver, British Columbia, on May 11 and was scheduled to arrive in Anchorage on Saturday.
Princess Cruises said in a statement that “our thoughts and prayers are with those who lost their lives and the families of those impacted by today’s accident”.
Ship passenger Cindy Cicchetti, said the ship captain announced that two planes had been in an accident.
She also said the ship would not leave as scheduled and that details were not provided as to how the accident could affect the rest of the cruise ship’s trip.
Weather conditions in the area where the crash happened Monday included high overcast skies with 9mph southeast winds.
The collision came nearly three years after a pilot and eight passengers died when a de Havilland DHC-3 Otter crashed in mountainous terrain near Ketchikan
The NTSB later determined that pilot error and lack of a formal safety programme were among the causes of the June 2015 crash.