US transit police officer charged with supporting the Islamic State

Nicholas Young reportedly bought nearly €223 of gift cards

US transit police officer charged with supporting the Islamic State

This file photo shows metro riders using the escalators in the Gallery Place-Chinatown Metro station in Washington | Image: Alex Brandon / AP/Press Association Images

A Washington transit police officer has been charged with attempting to provide material support to Islamic State, authorities say.

Nicholas Young (36) of Fairfax, Virginia, was arrested on Wednesday at police headquarters, the Washington Post said.

According to an affidavit, Young bought nearly $250 (€223) of gift cards he intended for IS to use to buy mobile phone apps that would facilitate communication.

But Young instead gave the gift cards to an undercover FBI source, it said.

Young - a veteran with the transport police department since 2003 - attempted to send the money over a messaging service the terrorist group uses for recruitment, Fox News reported.

The FBI has said he is the first law enforcement officer in the US to be charged with a terror-related offence.

Young will appear in federal court later on Wednesday.

Prosecutors said the Metro Transit Police initiated the investigation, and then worked with the FBI.

"Obviously, the allegations in this case are profoundly disturbing," Metro general manager Paul Wiedefeld said in a statement.

"They're disturbing to me, and they're disturbing to everyone who wears the uniform."

Metro spokesman Dan Stessel said Young had been fired as a result.

Documents show Young had been under surveillance since 2010, and travelled twice to Libya in 2011, where he said he joined rebel forces attempting to oust dictator Muammar Gaddafi.

Officials have said he did not pose any threat to the Metro system in Washington DC.