Iran's Revolutionary Guard has denied British allegations of a confrontation in the Strait of Hormuz, saying if it had received orders to seize any ships it would have executed them immediately.

The semi-official Fars news agency carried a statement from the Guard's navy early Thursday saying "there were no clashes with alien boats, especially English boats."

A picture shows supertanker Grace 1 off the coast of Gibraltar on July 6, 2019. Iran demanded on July 5, 2019 that Britain immediately release an oil tanker it has detained in Gibraltar, accusing it of acting at the bidding of the United States. [Photo: VCG]

Britain says three Iranian vessels unsuccessfully tried to impede the passage of a British commercial vessel through the Strait of Hormuz and only turned away after receiving "verbal warnings" from a UK navy vessel.

Last week, authorities in Gibraltar intercepted an Iranian supertanker that was believed to be breaching European Union sanctions by carrying a shipment of Tehran's crude oil to Syria. Tehran had warned of repercussions.

The tanker's detention comes at a particularly sensitive time as tensions between the U.S. and Iran grow over the unraveling of a 2015 nuclear deal, which President Trump withdrew from last year.