WASHINGTON — America has lodged a formal diplomatic protest with Iran over a weekend incident in which Iranian speedboats harassed American warships in the Persian Gulf, the State Department said today.

The protest, which repeats public American complaints about the “provocative” action, was sent to the Iranian Foreign Ministry through the Swiss Embassy in Tehran, which looks after American interests in Iran, a spokesman, Tom Casey, told reporters. He could not say if the Iranians had actually received and acknowledged receipt of the protest

“We have … prepared and given to the Swiss a diplomatic note formally protesting this incident,” he said. “It reiterates the points that we have made publicly in the last few days.”

“We certainly don’t want to see the Iranians taking any kind of provocative actions or provocative steps against our ships or against any ships that are transiting what is a primary international waterway,” Mr. Casey said.

He dismissed Iranian claims that there was nothing unusual about Sunday’s incident in the Strait of Hormuz as well as a videotape aired by Iranian television today that appeared to be an attempt to show there was no confrontation between the vessels.

“We all understand what happened in this incident,” Mr. Casey said.