Diplomatic tensions between the United States and Iran escalated on Friday as Tehran announced it would send warships close to American waters within months.

The Iranian Navy said it would deploy vessels in the Atlantic from March as a counter-measure to the presence of US aircraft carries in the Gulf.

Iranian Rear-Admiral Touraj Hassani said they would have a "continuous presence in international waters," which was intended to "wave the flag of the Islamic Republic of Iran" and "secure shipping routes".

The flotilla will include the Sahand, a new destroyer equipped with helicopters, surface-to-surface missiles, anti-aircraft guns, and electronic warfare capabilities.

It was the latest expansive naval move by the regime, which has also sent ships to the Indian Ocean and the Gulf of Aden to protect Iranian vessels from Somali pirates.

Last month Iran's navy said it was sending two or three ships on a mission to Venezuela.

Friction with Washington has ratcheted up since Donald Trump took office.

In May, Mr Trump announced he was withdrawing the US from the 2015 deal that restricted the country's nuclear ambitions, and reimposed sanctions on Iran's banking and energy sectors.

Iran has since threatened to block the Strait of Hormuz, through which one third of all crude oil traded by sea passes.