The founder of a volunteer group says it has found the remains of 13 more World War II Marines on a Pacific atoll.

Mark Noah, head of Marathon, Florida-based History Flight, tells The Associated Press that 12 sets of remains were found on Tarawa between January and March and a 13th set of remains was found this week.

The Pentagon's Defense POW/MIA Accounting Agency confirms more remains have been found, although it couldn't confirm the number. The agency says it will return the remains to the U.S. this summer.

Last year, Honor Flight found the remains of 35 Marines on Tarawa, which is part of the island nation of Kiribati, and the Defense Department found a 36th set.

All were returned to the U.S. The Pentagon says 23 of them have been identified.