DUBAI (Reuters) - Iran's navy warned a U.S. warship on Wednesday to leave waters near the Strait of Hormuz where the Iranians were testing submarines, destroyers and missile launchers, news agencies reported.

The commander of Iran's fleet, Rear-Admiral Habibollah Sayyari, told Tasnim news agency the U.S. ship was trying to collect information in the Sea of Oman - an area close to the Strait, a vital oil and gas shipping route - and said it left quickly after the alert.

There was no immediate reaction from Washington which this month joined other world powers in lifting sanctions on the Islamic Republic after Iran agreed to curtail its nuclear program.

In the days before that deal, Iran briefly detained 10 U.S. sailors after their boats entered its waters because of what they said was a navigational error.

"It was predictable that the U.S. warship would approach the area to collect information on (our) military operations. So we warned them twice in the morning ... to keep their distance from the exercise area and keep clear of our missile range for their own safety," Sayyari was quoted as saying by Tasnim.