The United States Coast Guard said Tuesday that the bodies of two people missing after the midair collision of two small planes on 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. on Monday and also injured 10 others, happened after one of the two planes descended by several hundred feet, officials said on Tuesday.

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,” Ms. 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.”