The U.S. Coast Guard said today that the bodies of two people missing after the midair collision of two small planes Monday in a remote part of Alaska had been recovered, bringing the number of people killed to six.

The collision, which happened at 12:12 p.m. Monday and also injured 10 others, happened after one of the two planes descended by several hundred feet, officials said today.

The two small planes, which were carrying cruise ship passengers, crashed Monday as they approached the city of Ketchikan, a National Transportation Safety Board member, Jennifer Homendy, said at a news conference.

“The preliminary data shows speed and altitude, but we don’t want to make any assumptions based on that,” Homendy said. “We still have to recover the planes and then we have to look at those, and it takes some significant work to understand how the two came together.”

Homendy said both planes were flying over George Inlet about 8 nautical miles from Ketchikan, which is a popular stop for cruise ships because of the extensive options for outdoor activities in the area.

The passengers had been on a Royal Princess cruise ship that left Vancouver, British Columbia, on May 11 for a seven-day “Voyage of the Glaciers” trip, the cruise line said.

The plane that descended, a DHC-3T Turbine Otter, was carrying 10 passengers and a pilot on an excursion that was sold through the cruise line, Homendy said.

It was returning from a tour of Misty Fjords, a national monument and wilderness area, Princess Cruises said in a statement. Ten of those people survived and one died, the company said. Homendy said investigators wanted to interview the pilot of that plane, who survived.

The plane was operated by Taquan Air, a regional airline based in Ketchikan that offers sightseeing tours and regularly scheduled flights. “We are devastated by today’s incident and our hearts go out to our passengers and their families,” Taquan said in a statement Monday.

The other plane, a DHC-2 Beaver owned by Mountain Air Service, was carrying four passengers and one pilot, Homendy said.

She said it was flying west-southwest toward Ketchikan at 106 knots, or roughly 125 mph, at an altitude of roughly 3,300 feet. The collision happened at an altitude of between 3,200 and 3,300 feet, she said.

The bodies of two passengers and the pilot, all Americans, were recovered overnight. The Ketchikan Fire Department identified the pilot tonight as Randy Sullivan.

Two more bodies were recovered later today.

Rescue efforts were continuing for the other passengers, one Australian and one Canadian, Princess Cruises said in a statement today.

Homendy said she expected investigators to spend between five and seven days at the crash site.

“We will not be determining the probable cause of the accident in that time frame nor will we speculate on the cause,” she said. “We will however provide information that we are able to provide that is factual in nature.”

Neither plane was equipped with cockpit voice recorders or devices to record flight data, nor were they required to be, Homendy said. Aaron Sauer, the NTSB investigator in charge, said the planes were “not in a controlled area” at the time of the crash, which meant their pilots were not required to be talking to an air traffic control tower.

Homendy said investigators would examine how the pilots were trained, any medical issues they may have had and log books they kept.

The investigation will also look into aircraft maintenance records, whether flight plans were filed with the Federal Aviation Administration, and whether the pilots had followed their company’s standard operation procedures, she said. Homendy also asked for any witnesses to come forward.

“We have requested flight data from the FAA including — we want to see if there were other planes operating in the area,” she said today.

More than 50 members of the Coast Guard were using helicopters and boats to search for the two missing people, said Lt. Brian Dykens, a Coast Guard spokesman.

Mischa Chernick, a spokeswoman for PeaceHealth Ketchikan Medical Center, said today that six patients who were admitted to the hospital were in fair condition, and four patients were evacuated to Seattle in stable condition.

It was not immediately known what company had operated the smaller plane, a de Havilland DHC-2 Beaver. The larger plane was a de Havilland DHC-3 Otter.

“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,” said Brian O’Connor, a spokesman for Princess Cruises.

The cruise ship was scheduled to arrive in Anchorage, Alaska, on May 18, Princess Cruises said.