Iran’s Revolutionary Guards have released 10 US sailors held for entering its territorial waters in the Gulf on Tuesday.

They were detained on Tuesday after one of their two vessels broke down during a training mission, the US says.

A statement read on state media said the group were released into international waters after apologizing.

It comes at a sensitive time, as the US and Iran try to implement the deal on Iran’s nuclear activities.

Earlier, the naval commander of Iran’s Revolutionary Guards, General Ali Fadavi, said he was satisfied a mechanical failure was behind the incursion.

“We have concluded that passage of Americans in our territorial waters was not a hostile passage or for espionage or similar acts,” he told Iranian television.

US Secretary of State John Kerry called Foreign Minister Javad Zarif shortly after the incident. The pair developed a personal rapport during the nuclear talks.

Those detained – nine men and one woman – were taken to Farsi Island, in the middle of the Gulf, where Iran has a naval base.