Iran's Foreign Ministry said Monday that a confrontation between Iranian boats and U.S. Navy ships in Gulf over the weekend was "something normal" and was resolved. It suggested the Iranian boats had not recognized the U.S. vessels.

The Pentagon said that in the incident early Sunday, five small Iranian boats repeatedly "charged" U.S. warships in the Gulf's Hormuz Strait and dropped boxes in the water. The boats warned the U.S. ships that they would set up "explosions," a U.S. Defense Department official said.

The U.S. craft were on the verge of opening fire when the Iranian boats fled, the official said, calling the incidident "the most serious provocation of its sort" in the Gulf. The official spoke on condition of anonymity because he was not authorized to speak on the record.

But Iranian Foreign Ministry spokesman Mohammed Ali Hosseini played down the incident, suggesting it was an issue of mistaken identity. He did not comment on the U.S. claims of the Iranian boats' actions.

"That is something normal that takes place every now and then for each party, and it (the problem) is settled after identification of the two parties," he told the state news agency IRNA.

The incident was "similar to past ones" that were resolved "once the two sides recognized each other."