Tensions between the US and Iran have escalated following the Islamic Revolutionary Guard Corps' downing of a US Global Hawk spy drone that Tehran claimed had violated Iran airspace in Hormozgan province. Trump initially stated that Iran had made "a very big mistake", but later stepped back from on his comment to retaliate.

US President Donald Trump approved a military operation against Iran after the downing of a US Global Hawk spy drone, but stepped back from launching it on Thursday night, The New York Times reported.

According to the report, military and diplomatic officials were expecting a strike order as late as 7 p.m. (23:00 GMT) Thursday. Prior to that ,there were heated debates at the White House involving Trump's top national security officials and leaders from Congress.

The outlet added, citing a senior Trump administration official, that aircraft and ships had been in position to fire missiles when the order came to cancel the operation.

Donald Trump initially approved attacks against a series of Iranian targets, including radar and missile batteries, The New York Times reported, citing multiple senior administration officials.

The operation, although underway, was abandoned in its early stages.

According to the report, it is not clear whether the attacks might still go forward.

The military operation was slated to take place before dawn Friday in Iran in order to "minimise risk to the Iranian military or to civilians," The New York Times reported.

CENTCOM described the downing of an American RQ-4 surveillance drone as an Iranian attempt to disrupt the ability of the US to monitor the area following recent threats to international shipping and the free flow of commerce, adding that the incident had occurred in international waters.

US President Donald Trump initially said Iran had made "a very big mistake", but later tempered his comments by suggesting to reporters that he doubted the drone's downing was intentional.

The US President also noted that the incident would have been far more serious if the aircraft had been a manned vehicle, saying that it would have made "a big, big difference".

The incident followed recent attacks on at least six oil tankers in the Persian Gulf region that the United States has blamed on Iran. Tehran in its turn has denied all the allegations.

Major General Hossein Salami, the commander-in-chief of Iran's elite Islamic Revolutionary Guard Corps, stated on Thursday that the country had downed a US drone to send a "clear message" to Washington.

"Iran is not seeking war with any country, but we are fully prepared to defend Iran," he said.

Iranian Foreign Minister Mohammad Javad Zarif has expressed Tehran's intentions to prove that the United States is lying in its claim that its drone was downed by the Iranian army in international airspace. To that end he tweeted a map showing the location of the downing of the US Global Hawk spy drone, noting Iran had retrieved “sections” of the military drone - which originated in the UAE - in Iranian territorial waters.

Tensions between Washington and Tehran have escalated since May 2018, when the US President scrapped the 2015 nuclear deal, which curbed Iran's nuclear programme, claiming that it failed to stop Iran's ballistic missile programme. The US administration has since adopted a "maximum pressure" policy aimed at pressuring the Islamic republic into negotiating a 'better' deal, but appears to have achieved quite the opposite so far.