Tehran sent an eerie warning to Washington Saturday that any attack would see its interests across the Middle East go up in flames.

The warning came on the heels of President Donald Trump’s confirmation that he called off a strike on three Iranian sites at the 11th hour.

The aborted US military action was to have been in response to Iran’s downing of a US reconnaissance drone, which has seen tensions between the two countries soar after a series of attacks on oil tankers the US has blamed on Iran.

“Firing one bullet towards Iran will set fire to the interests of America and its allies” in the region, armed forces general staff spokesman Brigadier General Abolfazl Shekarchi told the Tasnim news agency.

“If the enemy — especially America and its allies in the region — make the military mistake of shooting the powder keg on which America’s interests lie, the region will be set on fire,” Shekarchi warned.

President Donald Trump said Friday that the United States was “cocked & loaded” to strike Iran but pulled back at the last minute as it would not have been a “proportionate” response to Tehran’s shooting down of an unmanned drone.

Under pressure to respond to the high-stakes incident near the strategic Strait of Hormuz, Trump said the US was prepared to hit “3 different sites” Thursday night but that he scrapped the strikes “10 minutes” before they were to have been launched.

“I asked, how many will die. 150 people, sir, was the answer from a General,” the president tweeted, saying he concluded it would not have been “proportionate to shooting down an unmanned drone.”

The Pentagon says the Global Hawk drone — one of the most expensive pieces of equipment in the US arsenal, costing over $120 million apiece — was 34 kilometres (21 miles) from Iran when destroyed by a surface-to-air missile in an “unprovoked attack.”

It published a map of the drone’s flight path indicating it avoided Iranian waters, but Tehran provided its own map showing the aircraft inside its territory when it was downed by a domestically-manufactured Khordad 3 air defence battery.

The downing came with Iran already accused by Washington of carrying out attacks on tankers in the congested shipping lanes out of the Gulf.

Tehran denies any involvement.

Trump has repeatedly said he does not favour war with Iran unless it is to stop the country getting a nuclear weapon — something Iranian leaders insist they are not pursuing.

But critics say his policy of “maximum pressure” — including abandonment of an international deal to regulate Iran’s nuclear activities, economic sanctions and deployment of extra troops to the region — make war ever more likely.