Tensions have skyrocketed following Iran's shooting down of an American surveillance drone Thursday. 

A stunning Iranian video shows the moment a U.S. Navy drone was shot out of the sky. The clip purportedly shows forces firing a missile which collides with an object in the sky.

Meanwhile, in a video released by the U.S. government overnight, a smoke trail of the drone can be seen in black-and-white images as it plummets from the sky.

The Iranian Revolutionary Guard said its air force fired on the drone after it "violated" Iranian airspace, but the U.S. said the unmanned surveillance aircraft was flying in international airspace.

In Tehran, Foreign Minister Mohammad Javad Zarif announced late Thursday that parts of the drone had been recovered in Iranian territorial waters, as Tehran moved to bring the incident before the United Nations. 

"We don't seek war, but will zealously defend our skies, land & waters," Zarif said.

"At 00:14 U.S. drone took off from UAE in stealth mode & violated Iranian airspace," Zarif tweeted. "It was targeted at 04:05 at the coordinates (25°59'43"N 57°02'25"E) near Kouh-e Mobarak." "We've retrieved sections of the US military drone in OUR territorial waters where it was shot down." 

Iran's ambassador to the United Nations, Majid Takht Ravanchi, said in a letter to UN Secretary-General Antonio Guterres and the Security Council, saying the American drone was engaged in a "clear spying operation."

He called the flight a "blatant violation of international law."

The commander of Iran's Revolutionary Guard saying shooting down the drone sent "a clear message" to America. 

"We do not have any intention for war with any country, but we are fully ready for war," General Hossein Salami said in a televised address.

The Pentagon on Thursday released an image it said showed the flight path for the drone that was shot down by Iran, but did not immediately provide a detailed explanation of the image. 

The Pentagon also denounced the "unprovoked attack," claiming the navy drone was 34 kilometers (21 miles) from Iran when destroyed by a surface-to-air missile. But the Islamic Revolutionary Guard Corps said it brought the drone down as it was "violating Iranian air space" over the waters of Hormozgan province.

Trump played down the significance of Iran shooting down a U.S. drone over the Gulf, saying he found it "hard to believe" the move was intentional only hours after he had warned that Tehran had made a "very big mistake."

"I find it hard to believe it was intentional," Trump said on Thursday while receiving Justin Trudeau, Canadian prime minister, at the White House. "It could have been somebody who was loose and stupid that did it . . . But it was a very foolish move."

The White House held a classified briefing for lawmakers on Thursday afternoon. Afterwards, Nancy Pelosi, the Democratic speaker of the House of Representatives, urged the administration to avoid taking a "reckless” approach to the crisis.

"It is essential that we remain fully engaged with our allies, recognize that we are not dealing with a responsible adversary and do everything in our power to de-escalate," Pelosi said. "This is a dangerous, high-tension situation that requires a strong, smart and strategic, not reckless, approach."

Chuck Schumer, the top Democrat in the Senate, said he had made clear to Trump that he would need congressional approval for any military action against Iran.

Some critics are worried John Bolton, the hawkish national security adviser, will urge Trump to take military action against Iran. Asked on Thursday if some of his team were trying to push him into war, Trump said that was not the case.

"No, not at all. Not at all. In fact, in many cases, it's the opposite," Trump said. "I said I want to get out of these endless wars. I campaigned on that . . . But this is something, this is a new wrinkle. This is a new fly in the ointment, what happened shooting down the drone. And this country will not stand for it, that I can tell you."

(Cover:  A RQ-4 Global Hawk drone conducts tests over Naval Air Station Patuxent River, Maryland, U.S. in this undated U.S. Navy photo. /VCG Photo)

(With input from agencies)