Iran released ten U.S. sailors Wednesday after holding them overnight, bringing a swift end to an incident that had rattled nerves days ahead of the expected implementation of a landmark nuclear accord between Tehran and world powers. Iran's Islamic Revolutionary Guards Corps (IRGC) said it had freed the sailors after determining they had entered Iranian territorial waters by mistake. “Our technical investigations showed the two U.S. Navy boats entered Iranian territorial waters inadvertently,” the IRGC said in a statement carried by state television. “They were released in international waters after they apologized,” it added. The sailors had been detained aboard two U.S. Navy patrol boats in the Gulf on Tuesday. Confirming the sailors' safe release, the Pentagon said there were no indications they were harmed while in Iranian custody.