Retired Delta Force vet reveals biggest challenge in Maduro capture mission in Venezuela

John McPhee, who served in the U.S. Army's elite special operations unit, told "Fox & Friends Weekend" on Sunday that the greatest challenge of the mission came before operators reached their target.

"I'd say the most difficult task is knocking out all the air defenses and getting the guys in on the ground," McPhee said. "Once the guys are on the ground, they can handle themselves. However, you gotta get to the fight if you're gonna have a fight."

McPhee emphasized that operations of this scale require extensive preparation and coordination. 

"Something like this would take months to kind of plan, get organized. But once the guys figure this out, there's no stopping them," he said.

"All those tiny details were gone over, polished out, so there were no tiny details that could stop anything that these guys did."

He said the mission highlights how refined the force has become, adding that America can "use a ground force like nobody has used in history."

"These guys plan for this, they train for this. Basically, they spend their whole adult lives for this one mission," McPhee said. 

No Americans were killed during the mission, a feat praised by Trump. 

Fox News' Michael Dorgan, Rachel Wolf, David Spunt and Lucas Tomlinson contributed to this report.