The report comes amid increased tensions between Iran and the US, with Washington announcing a new deployment of additional forces to the Middle East, including a Patriot missile battalion, drones and manned surveillance aircraft.

According to an unnamed US official cited by Reuters, a US Navy MQ-4C Triton had been shot down by an Iranian surface-to-air missile in international airspace over the Strait of Hormuz.

There has been no official confirmation from the Pentagon, although US Central Command spokesman Capt. Bill Urban earlier asserted that "There was no drone over Iranian territory," according to AP.

The comment follows a report by the state-run IRNA news agency, citing Islamic Revolutionary Guard Corps, claiming that Iran had shot down a US Northrop Grumman RQ-4 Global Hawk spy drone flying over Hormuzgan province.

The drone was downed when it entered Iranian airspace near the Kouhmobarak district in southern Iran's Hormuzgan province, according to IRNA.

Tensions in the Gulf area escalated over the past week as a number of oil tankers from various nations have been attacked in the region. The US and its regional allies claim that Iran had a role in the incidents, while Tehran has denied the allegations.

Against the backdrop of the attacks against tankers, US Acting Secretary of Defence Patrick Shanahan said in a Monday statement that the Pentagon has authorized the deployment of an additional 1,000 troops for defensive purposes "to address air, naval, and ground-based threats in the Middle East".

In a claim voiced last week, Washington said that the IRGC allegedly attempted to down one of its drones prior to attacking the vessels in the Gulf of Oman, but failed to reach its target.