The US Navy says envoys from 41 nations have gathered in Bahrain to begin anti-mine drills in the Persian Gulf amid efforts by Iran to expand its naval presence there.

The US-led exercises, which run through May 30, mark the second major show of maritime cooperation in the Gulf in less than a year.

Although the Navy says the drills are not specifically tailored to counter Iranian threats, Iran has previously warned it could block critical Gulf oil routes in retaliation for Western sanctions over Tehran's nuclear program. Iran also has sought to expand its naval capabilities, including plans to launch new submarines.

A Navy statement Monday says the drills will begin with onshore training and then move to the Gulf for maneuvers including mine-sweeping and search-and-seizure operations.