Iran’s Revolutionary Guard Corps has released 10 U.S. Navy sailors who were being held after their boats are said to have drifted into Iranian waters on a journey from Kuwait to Bahrain Tuesday.

“Ten U.S. Navy Sailors safely returned to U.S. custody today, after departing Iran. There are no indications that the Sailors were harmed during their brief detention,” according to a statement from the U.S. Naval Forces Central Command Public Affairs Office.

“The Sailors departed Farsi Island at at 8:43 a.m. GMT, aboard the two Riverine Command Boats (RCB) that they had been operating when they lost contact with the U.S. Navy. The Sailors were later transferred ashore by U.S. Navy aircraft, while other Sailors took charge of the RCBs and continued transiting toward Bahrain, the boats’ original destination. The Navy will investigate the circumstances that led to the Sailors’ presence in Iran,” the statement added.

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Secretary of State John Kerry said in a statement, “I’m very pleased that our Sailors have been safely returned to U.S. hands. As a former Sailor myself, I know the importance of naval presence around the world and the critical work being done by our Navy in the Gulf region. I’m proud of our young men and women in uniform and know how seriously they take their responsibilities to one another and to other mariners in distress.”

Cmdr. Kevin Stephens, spokesman for U.S. Fifth Fleet, told ABC News the sailors were recovered aboard Navy cruiser USS Anzio, which was in international waters, just outside Iranian territorial waters. Once on board, they were given an initial medical evaluation and were flown to the aircraft carrier USS Harry S. Truman. They will receive additional assessments on board before being taken ashore to a facility in the region, although that may not be Bahrain.

The sailors are now undergoing the reintegration process set up by Joint Personnel Recovery Agency, Stephens said, adding that “the first concern was the sailors, the second is ensuring they get the best care they can get and successfully reintegrate into the force, and third is understanding the circumstances of the incident.”

It’s believed the incident occurred when one of the two small U.S. Navy boats had mechanical problems and that both of the boats may have drifted into the Iranian waters, a U.S. official said Tuesday.

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The craft were supposed to have been refueled by another U.S. Navy ship in the Gulf so it could complete the journey from Kuwait to Bahrain, the U.S. official said Tuesday, but never made it to the refueling craft.

Secretary of Defense Ash Carter released a statement, saying, “I am pleased that ten U.S. Navy sailors have departed Iran and are now back in U.S. hands. I want to personally thank Secretary of State John Kerry for his diplomatic engagement with Iran to secure our sailors’ swift return. Around the world, the U.S. Navy routinely provides assistance to foreign sailors in distress, and we appreciate the timely way in which this situation was resolved.”

Iran’s Revolutionary Guard Corps said the U.S. military vessels were carrying armed personnel when they entered Iran’s waters and were seized by IRGC naval units, according to Iranian media. The vessels were then transferred to Farsi Island.

This is a breaking news story. Check back for updates.