The US mission to capture Venezuelan President Nicolas Maduro was planned over many months and involved more than 150 aircraft.
General Dan Caine, the chairman of the Joint Chiefs of Staff, said US intelligence agencies had tracked Maduro to "understand how he moved, where he lived, where he travelled, what he ate, what he wore".
"The operation, known as Operation Absolute Resolve, was discreet, precise and conducted during the darkest hours of January 2, and was the culmination of months of planning and rehearsal — an operation that frankly only the United States military could undertake," Caine said in a press conference at Mar-a-Lago with US President Donald Trump.
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CNN previously reported that the CIA had installed a small team inside Venezuela over the northern hemisphere summer to keep a close watch on Maduro's activities.
Caine said Operation Absolute Resolve involved more than 150 aircraft launched from 20 different bases on land and sea.
Among them were helicopters carrying an extraction force that began their flight into Venezuela at just 30 metres above the water.
The helicopters, safeguarded by a series of strikes carried out in the area, arrived at Maduro's compound about 1am ET (5pm AEDT).
The effort to capture Maduro and his wife, Cilia Flores, required multiple "self defence engagements" as the forces came under fire, Caine said, before flying out of Venezuela about 3.29am ET (7.29pm AEDT).
Maduro and his wife were subsequently transferred to the warship USS Iwo Jima, where they were then on their way to New York to stand trial.
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"Failure of one component of this well-oiled machine would have endangered the entire mission, and failure is never an option for America's joint force," Caine said.
CNN reports on a source saying "a handful of troops sustained bullet and shrapnel wounds, but none are life-threatening".
Trump earlier told Fox News that "a couple of guys were hit. But they came back and they're supposed to be in pretty good shape."
Caine said one US aircraft was struck during the operation, "but remained flyable".
He also highlighted the role of intelligence teams in supporting the mission in real time.
"Our air and ground intelligence teams provided real time updates to the ground force, ensuring those forces could safely navigate the complex environment without unnecessary risk."
Maduro was 'trying to get into safe place'
Trump said Maduro could have been killed.
"It could have happened," he said.
"He was trying to get into a safe place. You know, the safe place's all steel, and he wasn't able to make it to the door because our guys were so fast."
The US military "went through the opposition so fast", Trump said, while also noting that "there was a lot of opposition".
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"People were wondering, do we get them by surprise? Sort of surprised, but they were waiting for something. It was a lot of opposition. There was a lot of gunfire," he said.
Trump said lights in Caracas were shut off during the operation.
"No nation in the world could achieve what America achieved yesterday," Trump said this morning.
"In just a short period of time, all Venezuelan military capacities were rendered powerless as the men and women of our military, working with us, law enforcement, successfully captured Maduro in the dead of night.
"It was dark, the lights of Caracas were largely turned off due to a certain expertise that we have.
"It was dark and it was deadly."
US prepared for second wave of attack
Trump praised the US operation, calling it a success and emphasising that no American service members were killed and no US military equipment was lost.
He said it involved extensive US military assets.
"If you would have seen what I saw last night, you would have been very impressed," Trump said.
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"I'm not sure that you'll ever get to see it, but it was an incredible thing to see not a single American service member was killed and not a single piece of American equipment was lost.
"We had many helicopters, many planes, many, many people involved in that fight."
Trump said the US was prepared to mount a second attack on Venezuela.
"We were prepared to do a second wave if we needed to do so — we actually assumed that a second wave would be necessary, but now it's probably not," he said.
"The first wave, if you'd like to call it that, the first attack was so successful, we probably don't have to do a second, but we're prepared to do a second wave, a much bigger wave, actually."
- Reported with CNN