The wait for the sailors’ release Wednesday morning dragged on for hours, with Iranian officials interrogating the sailors about their motives and demanding a U.S. apology.

But an Iranian Revolutionary Guard Corps spokesman told state-run media the boats strayed into Iranian waters by accident.

“The evidence suggests that they unintentionally entered the Iranian waters because of the failure of their navigational system,” IRGC spokesman Ramazan Sharif said.

So on Wednesday afternoon, the sailors traveled on their two boats to a rendezvous point in the Persian Gulf, a U.S. official said. They were escorted by Iranian boats, which turned back when they reached the rendezvous point in international waters.

The sailors then boarded the guided missile cruiser USS Anzio, where they were undergoing medical checks Wednesday.

“There are no indications that the Sailors were harmed during their brief detention,” the U.S. Navy said in a statement.