(Updated 12:15 p.m. EDT) -- Two float planes carrying Royal Princess cruise passengers collided mid-air Monday outside Ketchikan, Alaska, resulting in the death of six people, according to the United States Coast Guard's latest statement early Wednesday morning.

Ten people were rescued Monday as part of a joint effort between the Coast Guard, which is leading the investigation, and partner agencies and good Samaritans; the conditions of the 10 people have not been disclosed.

The crash occurred at 1:08 p.m. local time (5:08 p.m. Eastern) about eight nautical miles from Ketchikan, according to a statement from Princess Cruises. The National Transportation Safety Board has yet to determine a cause.

One of the planes, operated by Taquan Air, was returning from a Misty Fjords flightseeing excursion sold by the line, with 10 Royal Princess cruise passengers and one pilot onboard. The other plane, which Princess Cruises said carried four cruise passengers in addition to the pilot, was run by an independent tour operator.

Among the 10 survivors are nine American cruise passengers and the pilot, all who were on the Taquan Air plane. Authorities have confirmed the six fatalities include one American cruise passenger from the Taquan Air plane and three more Americans -- two cruise passengers and the pilot -- from the independently operated plane. One Australian and one Canadian also died in the crash.

Princess Cruises has sent members of its Care Team to provide support to families affected by the incident.

"All of us at Princess Cruises are deeply saddened by this tragic news and we are extending our full support to the investigating authorities as well as the traveling companions of the guests involved," Princess Cruises' spokesperson Brian O'Connor said. "We immediately activated our Princess Care Team employees in the region and sent additional team members to Ketchikan overnight to assist the families impacted."

Cruise Critic members onboard Royal Princess have been posting updates to the Princess Cruises forums.

Said idahospud: "Counselors are available for passengers and crew. We have a very sad ship right now. Please keep the families and friends in your thoughts and prayers … I learned at the Most Traveled Guest gathering [Monday night] that Princess also disembarked some staff members tasked to provide support to the families involved. Kudos to Princess."

He added: "We are leaving port now and will arrive late in Juneau. Excursions are being rearranged, and if passengers are booked on any flightseeing excursions during the rest of the voyage they can ask for for a full refund if they wish to cancel."

Said another member onboard, Easyrider949: "The Royal just pulled away from the port and now heading for Juneau. We won’t get there until 10:00 am [Tuesday]. The mood onboard is quiet and somber. Our prayers go out the all passengers involved and friends and relatives still onboard."

Ketchikan was the first stop on Royal Princess' seven-night cruise, which departed May 11 from Vancouver. It is scheduled to arrive May 18 in Whittier.

The float plane collision follows a similar incident that took place in July 2015, involving Holland America Line cruise passengers. All nine passengers onboard the plane, including the pilot, died in the 2015 crash, which also occurred outside Ketchikan.

Learn more about flightseeing shore excursions, including the risks involved and precautionary measures you can take, in our feature, Q&A: Are Flightseeing Shore Excursions Safe?