The US Secret Service dealt with at least one credible assassination threat against Donald Trump on his visit to the Philippines last year.
Agents tracked a man who was heading in the direction of the president's hotel after posting on Twitter "Gonna be in Manila the same time as Trump… I’ll take one for the team."
They also swarmed a park in Manila after identifying a known Isis operative who was meeting with an associate there.
Both threats were revealed in a National Geographic documentary United States Secret Service: On the Front Line, which went behind the scenes with agents.
The agents picked up the threatening tweet which was accompanied by a picture of Lee Harvey Oswald.
On the suspect's Instagram account they found a picture of a book called The Definitive History of the Assassin.
Twenty minutes before the president, whose Secret Service codename is "Mogul," arrived in Manila for a summit in November, agents were also trying to locate the exact whereabouts of an Isis operative known to be in the city.
Special Agent Chad Ragan was seen in the documentary shouting into a phone: "What is going on proactively to track this guy down? I need an update. Now."
The operative was tracked to Luneta Park, a mile from the president’s hotel, which was then inundated by Philippines police officers, and the suspects were arrested.
Special Agent Ragan told the Daily Beast: "With technology, that was one of the things that was a blessing for us, because we were able to know that he was moving close to us, where he was, and track him. That was a huge piece of stopping the threat."