At least four people are dead and 10 others hospitalized after two floatplanes collided in midair on Monday near the southeast Alaska town of Ketchikan.

The pilot on each plane was flying cruise ship passengers on tours of Misty Fjords National Monument in the nearby Tongass National Forest, Princess Cruises said in a statement. All aboard a de Havilland DHC-2 Beaver died, the cruise line said. The other plane, a de Havilland Otter DHC-3, carried 11 people.

Ten people were being treated at Peace Health's Ketchikan Medical Center. One person is in critical condition, three are in serious condition and six people are in fair condition, Peace Health Communications Director Beverly Mayhew told USA TODAY.

Princess Cruises confirmed five fatalities in a statement. The U.S. Coast Guard, however, has put the figure at four dead. One person remains missing, according to Princess Cruises. The Coast Guard says two people were missing, according to Petty Officer Jon-Paul Rios.

“It’s been a long day and the crews have been working really hard to rescue people and recover the deceased. They’re still working on a search and recovery of three more individuals,” Deanna Thomas, a spokeswoman for the Ketchikan Gateway Borough, the local government, said Monday evening.

The planes crashed under unknown circumstances, said Federal Aviation Administration spokesman Allen Kenitzer.

A spokesperson for Taquan Air, which operated the plane carrying 11 people, said the company is cancelling flights while federal authorities investigate the incident.

“At this time, we are in the midst of an active crisis response, and our focus is on assisting these passengers, the pilot, our staff, their families and loved ones, and first responders," Taquan said in a statement.

Weather conditions at the time of the crash included high overcast skies with 9 mph southeast winds.

The cruise ship Royal Princess had departed Vancouver last weekend for a planned seven-day cruise, ending in Anchorage.

"We are deeply saddened to report this news and our thoughts and prayers are with those who lost their lives and the families of those impacted by today’s accident," Princess Cruises said in a statement.

Sightseeing crash:Pilot disoriented in fatal Alaska tour-flight crash

Emergency declared:Boeing 737 makes emergency landing in Tennessee following a 'potential mechanical issue'

A passenger on the ship, Cindy Cicchetti, said the ship is not leaving as scheduled because of the crash.

In 2015, a floatplane crashed into a mountain northeast of Ketchikan, killing all nine people aboard. The pilot got disoriented in cloudy weather while his company pressured him to get back to a cruise ship before it departed, federal investigators determined.

In the eight years before the accident, Alaska recorded four fatal air-tour flight crashes involving cruise ship passengers, Robert Sumwalt, acting chairman of the National Transportation Safety Board, said at the time.

Floatplanes have pontoons mounted under the fuselage so they can land on water.

Contributing: The Associated Press