TEHRAN, Iran — All 10 U.S. Navy sailors detained by Iran after their two small boats allegedly drifted into Iranian territorial waters around one of Iran’s Persian Gulf islands a day earlier have been freed, the United States and Iran said Wednesday.

The sailors’ swift release quickly diffused what could have escalated into an international crisis days before Iran is expected to meet the terms of last summer’s nuclear deal with world powers. The deal gives Iran significant relief from painful economic sanctions.

The nine men and one woman were held at an Iranian base on Farsi Island after they were detained nearby on Tuesday. The tiny outpost has been used as a base for Revolutionary Guard speedboats as far back as the 1980s.

The Navy said there were no indications they had been harmed while in custody.

The sailors departed the island at 0843 GMT aboard the boats they were detained with, the Navy said. They were picked up by Navy aircraft and other sailors took control of their boats for the return voyage to Bahrain, where the U.S. 5th Fleet is based.

The sailors will be taken ashore somewhere in the region so that they can receive support to reintegrate with their unit, said 5th Fleet spokesman Cmdr. Kevin Stephens. He declined to say where they were traveling to or provide details on their identities. Stephens said the priority now is “determining … how exactly these sailors found themselves in Iran. And that’s something we’re going to be looking at.”

The Revolutionary Guard’s official website published images of the detained U.S. sailors before their release, showing them sitting on the floor of a room. They look mostly bored or annoyed, though at least one of the sailors appears to be smiling. The sole woman had her hair covered by a brown cloth. The pictures also showed what appeared to be their two boats.

“After determining that their entry into Iran’s territorial waters was not intentional and their apology, the detained American sailors were released in international waters,” a statement posted online by the Guard said Wednesday.

Vice President Joe Biden, speaking later to “CBS This Morning,” denied that Americans made any apology.