Iran denied on Saturday US accusations that its fast-attack boats were "harassing" warships at the mouth of the Persian Gulf, and said Washington would be responsible for any clashes in the key oil shipping route.

US Navy commanders earlier accused Iran of jeopardizing international navigation by "harassing" warships passing through the Strait of Hormuz and said future incidents could result in "miscalculation" and lead to an armed clash.

They spoke after the US aircraft carrier, George H.W. Bush, confronted what one of the commanding officers described as two sets of Iranian Navy fast-attack boats that had approached a US-led, five-vessel flotilla as it entered the Strait on Tuesday on a journey from the Indian Ocean into the Gulf.

It was the first time a US carrier entered the narrow waterway, where up to 30 percent of global oil exports pass, since President Donald Trump took office in January pledging a tougher US stance towards Iran.

In Tehran, Brigadier General Masoud Jazayeri, deputy chief of staff of Iran's armed forces, said the US claims of the confrontation in the Gulf were based on "false reports or ulterior motives", the state news agency IRNA reported.

"We emphasize that the Americans would be responsible for any unrest in the Persian Gulf, and again warn that the US military must change its behavior," Jazayeri said, without elaborating.

US commanders earlier said Tuesday's incident, in which the George H.W. Bush sent helicopter gunships to hover over the Iranian speedboats as some came as close as 950 yards (870 meters) from the aircraft carrier, ended without a shot being fired. The encounter with Iranian Navy boats occurred as the USS George H.W. Bush was en route to the northern part of the Gulf to participate in US-led air strikes against ISIL terrorists in Iraq and Syria.

(Source: Reuters)