The US has apologised to Iran after 10 American sailors were arrested for entering Iranian waters, the commander of Iran's Revolutionary Guards naval forces has said.
General Ali Fadavi accused those detained of "unprofessional" acts.
But he suggested the group, who are being held by the guards, could be released soon.
Despite last year's breakthrough nuclear deal tensions remain between the US and Iran.
US Secretary of State John Kerry contacted Iranian Foreign Minister Javad Zarif over the incident.
Giving his assessment of the talks, Gen Fadavi said "Mr Zarif had a firm stance, saying that they were in our territorial waters and should not have been, and saying that they [the US] should apologise".
"This has been done and it will not take long, and the naval force, according to its hierarchy, will act immediately upon the orders it receives," he added.
Tuesday's incident happened near Farsi Island in the middle of the Gulf.
An unnamed official told the Associated Press that Mr Kerry "personally engaged with Zarif on this issue to try to get to this outcome".
Mr Kerry and Mr Zarif developed a personal relationship throughout three years of negotiating a nuclear deal.
The conservative Tasnim news agency reported that the American boats were equipped with machine guns.
"Frequent calls by US officials urging Tehran to free the detainees continues," reads the Tasnim report.
The Revolutionary Guard has aggressively protected Iranian sea borders in the past.
Fifteen British sailors and marines were held for 13 days in 2007 after they were captured in disputed area between Iran and Iraq.
Tensions between Iran and the US remain despite the breakthrough nuclear deal.
In December, Iran's navy conducted rocket tests near US warships and other commercial vessels in the Strait of Hormuz.
The tests were "highly provocative", a US military commander said at the time.