Iranian fast patrol boats confronted a U.S. Navy vessel in international waters in the Persian Gulf Sunday, and one of the boats came to a stop in the path of the U.S. boat, forcing it to take evasive action to avoid a collision.

No shots were fired in the encounter, but the Pentagon called the confrontation "another example of an unsafe and unprofessional interaction" with the Islamic Revolutionary Guard Corps Navy in the Gulf.

A Pentagon spokesman said seven Iranian fast patrol boats approached the USS Firebolt, a coastal patrol boat, and that three of the boats followed the boat at a distance of about 500 yards.

"Eventually the boats broke off their pursuit, but one turned toward the USS Firebolt, and came to stop directly in front of the ship," said spokesman Capt. Jeff Davis. "This caused the Firebolt to have to maneuver to avoid collision."

Davis said the Firebolt missed the Iranian vessel by about 100 yards.

"During the interaction, the Firebolt attempted multiple radio communications with the Iranians," Davis said, but there was no response.

The Iranian boats had their weapons uncovered and manned, but the guns were not trained on the Firebolt.

The Pentagon again called on Iran to stop harassing U.S. ships and reiterated that all U.S. Navy vessels have the right to defend themselves if threatened. The Firebold incident was the latest in a string of provocative Iranian actions against U.S. Navy vessels in the Gulf.

Last week, the head of the U.S. Central Command said he feared "rogue commanders" could provoke a miscalculation with U.S. ships that could end badly for the Iranians.

U.S. Central Commander Gen. Joseph Votel said that up to now, the U.S. Navy has responded to the provocations in a highly professional manner, but warned "ultimately if they continue to test us we're going to respond and we're going to protect ourselves and our partners."