The US State Department has seized the passport of former Marine and UN weapons inspector Scott Ritter, he told RT on Monday.

Ritter was on his way to Russia for the St. Petersburg International Economic Forum (SPIEF) when he was pulled off the plane and had his documents confiscated.

“I was boarding the flight. Three [police] officers pulled me aside. They took my passport. When asked why, they said ‘orders of the State Department’. They had no further information for me,” Ritter told RT. “They pulled my bags off the plane, then escorted me out of the airport. They kept my passport.”

“Was this done in accordance with the First Amendment, or the Fourth,” Russian Foreign Ministry spokeswoman Maria Zakharova said, commenting on the news. The first amendment to the US constitution protects freedom of speech, press and assembly, while the fourth bars the government from “unreasonable searches and seizures.”

Ritter is a former US Marine Corps intelligence officer, who later served as the US and UN weapons inspector in Iraq. He is also a RT contributor, writing about international security, military affairs, Russia, and the Middle East, as well as arms control and nonproliferation.

He most recently visited Russia in January, spending time in Chechnya, Moscow and St. Petersburg, among other places.

The most recent post on Ritter’s Telegram channel put the Clooney Foundation for Justice on notice for its alleged crusade against “Russian propagandists.”

“Here I am. In your face. If telling the truth about Russia makes me a propagandist in your book, then I accept the title,” he wrote. “Bring it on. I’ll school you on the First Amendment.”

“You have zero concept of what free speech is. Try and arrest me and you’ll find out. In spades. It’s war,” he added.