NEW YORK - Seated on the floor of a villa in north-east Teheran around a tablecloth spread with platters of saffron chicken and rice with barberries, about 30 officials of Iran's Revolutionary Guard and guests gathered last Thursday (June 20) night for a prayerful celebration.

"A special blessing for the commander who ordered the attack on the American drone and for the fighters who carried it out," a preacher declared, as recalled by one of the guests present, who said a raucous chorus of "amen" arose from the room.

Their success earlier that day at shooting down an unmanned US Global Hawk surveillance drone - list price US$131 million (S$177.5 million) - surprised even some leaders of the Revolutionary Guard. They had wondered themselves whether they could hit a US target so high in the sky, according to the guest.

In fact, the Revolutionary Guard sought to take out the drone in large part to prove they could do it, according to that guest and four other Iranians, including two senior current members. The others were two former Guard members and one who is affiliated with the elite military unit, which reports directly to Supreme Leader Ayatollah Ali Khamenei and operates outside the control of Iranian elected officials.

Guard leaders, these people said, had been incensed by recent statements from US officials belittling Iran's military prowess, like an accusation by Mr Brian Hook, the State Department's special envoy for Iran, that Iran had "photoshopped antiquated aircraft" to overstate its capabilities.

And now, these people said, the Guard leaders feel even further vindicated by the news that - as they celebrated into the night in Teheran - President Donald Trump was simultaneously pulling back at the last minute from a retaliatory airstrike he had ordered just hours before.

While Mr Trump's advisers have argued his contemplation of a strike should stand as a warning to Iran, some Guard leaders appear to have concluded the opposite: that Trump is determined to avoid a fight, and that the downing of the drone has strengthened their hand in any future negotiations.

"What happened in the past 48 hours was extremely important in showing Iran's strength and forcing the US to recalculate," said Mr Naser Imani, a political analyst who was formerly a member of the Revolutionary Guard's political bureau. "No matter how you look at it, Iran won."

How widely or deeply those sentiments are shared within the Iranian government could not be determined. Discussions within the Guard, a powerful wing of Iran's armed forces, are highly secretive, and the people who described those discussions spoke on condition of anonymity for fear of reprisals.

The public bravado of voices close to the Guard, like Mr Imani, could mask deeper worries about the superior strength of the US military.

Retired General Jack Keane, who has close ties to Mr Trump, said on Friday that US intelligence had learned that "Iranian national leaders" - including at least one senior commander in the Revolutionary Guard - "were frustrated or furious with the tactical commander who made the decision to shoot down the American drone".

Any indications of the thinking among Guard leaders, though, are significant, in part because of its singular role in both the formulation and execution of Iranian national security and foreign policy.

It is the branch of the Iranian military that operates around the region, often training and arming local militias to thwart US policies or interests in places like Iraq, Syria or Lebanon. The Trump administration, as part of its intensified sanctions against Iran, designated the Guard as a foreign terrorist organisation in April.

Although the Guard has backed local militias in Iraq who attacked US soldiers, the organisation itself has seldom hit US targets directly.

But last week was not the first time the Guard has claimed triumph in downing an unarmed US drone. In 2011, its computer hackers evidently sabotaged a radar-evading RQ-170 Sentinel surveillance drone, which US officials said had been flying over Afghanistan but ended up landing in northern Iran because of a malfunction.

The US did not retaliate for the loss of the drone. Then President Barack Obama said the US had "asked for it back", but the Iranians instead claimed to have reverse engineered it and even produced toy replicas for children.

Until recently, Guard commanders and other Iranian leaders had appeared to refrain from direct confrontations with the US military, even after Mr Trump withdrew in May 2018 from the 2015 deal to lift economic sanctions in exchange for limits on Iran's nuclear programme and began to reimpose harsh sanctions.

The Guard's naval forces continued to avoid skirmishes with US forces in the Persian Gulf that had once been a regular occurrence. And the Guard declined any attempt to retaliate against Israel after it repeatedly attacked Guard operations inside Syria, analysts said.

That posture changed in the past few months when the Trump administration designated the Guard as a terrorist group and added sanctions to block Iran's oil sales, a critical revenue source for the country.

With oil revenue plummeting while unemployment and inflation were soaring, Iranian leaders denounced the sanctions as economic warfare and declared that they would take steps to restart their nuclear programme.

The US has also accused Iran of planting naval mines that damaged six tankers in two incidents in the waters around the Persian Gulf, and Western officials say those attacks were carried out by the Guard - although Iranian leaders have disclaimed responsibility.

The US Cyber Command last Thursday conducted online attacks against an Iranian intelligence group that US officials believe helped plan the attacks against oil tankers, according to people briefed on the operation.

As tensions escalated, Republican Senator Tom Cotton from Arkansas a leading advocate of confronting Iran, raised alarms in Teheran by declaring in a television interview in May that a war with Iran would require only "two strikes, the first strike and the last strike".

Then this month, Mr Hook, the US special envoy for Iran, seemed to all but dismiss Iranian defences and accuse Teheran of lying about them.

"Iran has photoshopped images of missile launches to try and show its increased missile capability," he said in a video message released by the State Department.

Their comments - both quickly derided in Iranian state media - helped convince Guard leaders to show off their missiles to deter an attack, according to several Iranians in or close to the Guard.

"American officials like Mssrs. Hook and Cotton are underestimating Iran's military capabilities," said Foad Izadi, a conservative professor at Tehran University and a commentator for Guard publications. "This is an impression that Iranian leaders wanted to correct. Iran needed to send this message to the other side that attacking us would be extremely costly."