A group of US sailors have been detained by Iranian officials after their vessels were stopped in the Gulf, a US official says.
"We lost contact with two small US naval craft en route from Kuwait to Bahrain," the official told the BBC.
The US has been told the sailors are safe and "will promptly be allowed to continue their journey".
The incident occurred near Farsi Island after one of the ships encountered mechanical problems.
US Secretary of State John Kerry immediately called Iranian Foreign Minister Javad Zarif to begin negotiations after hearing about the incident.
The BBC reports Mr Kerry "personally engaged with Zarif on this issue to try to get to this outcome".
However, it is not clear when the sailors will be released.