WASHINGTON: Iran was holding 10 US Navy sailors and their two small Navy boats after the boats had mechanical problems and drifted into Iranian waters, but American officials have received assurances from Tehran that they will be returned safely and promptly.

Pentagon spokesman Peter Cook told The Associated Press that the riverine boats were moving between Kuwait and Bahrain when the US lost contact with them.

US officials said that the incident happened near Farsi Island, situated in the Arabian Gulf. They said that some type of mechanical trouble with one of the boats caused them to run aground and they were picked up by Iran. The sailors were in Iranian custody on Farsi Island at least for some time, but it’s not certain where they are now.

The semi-official Iranian news agency, FARS, said the Iranian Revolutionary Guard’s navy has detained 10 foreign forces, believed to be Americans, and said the sailors were trespassing in Iranian waters.

“We have been in contact with Iran and have received assurances that the crew and the vessels will be returned promptly,” Cook said.

The incident comes amid heightened tensions with Iran, and only hours before President Barack Obama is set to deliver his final State of the Union address to Congress and the public. It set off a dramatic series of calls and meetings as US officials tried to determine the exact status of the crew and reach out to Iranian leaders.