A US man who prosecutors say was on his way to Syria to join an al-Qaeda splinter group has been arrested near the US-Canada border in Washington state on a "terrorism" charge, officials said.

The US Department of Justice said in a statement that 20-year-old Nicholas Teausant, an American-born convert to Islam, had planned to cross into Canada and travel on to Syria to join a rebel group.

I'm going to be a commander and I'm going to be on the front of every single newspaper in the country.

Nicholas Teausant

Arrested near the Canadian border, Teausant was charged with attempting to provide material support to a "foreign terrorist organisation", as he planned on joining the Islamic State of Iraq and the Levant (ISIL).

Investigators said Teausant discussed his scheme at length with a paid FBI informant, repeatedly affirming that he was serious about leaving for Syria.

The informant put Teausant in contact with a undercover federal agent who approved his efforts to join rebel fighters before he was apprehended.

Beginning last year, Teausant began expressing a desire to see America's downfall, saying on the internet: "I would love to join Allah's army but I don't even know how to start."

He took to another online forum to say he hoped to fight in Syria. "I'm going to be a commander and I'm going to be on the front of every single newspaper in the country," he said.

Among Teausant's plans was to appear in videos for the group, without covering his face and be "the one white devil that leaves their face wide open to the camera."

Foreign fighters

Teausant is said to have wanted to join ISIL and fight against the Western-backed Free Syrian Army rebel group, which is also battling the government of President Bashar al-Assad.

Teausant also spoke of wanting to target the subway system in Los Angeles on New Year's Eve or New Year's Day, according to the prosecutors, but discontinued his involvement over fears authorities had been tipped off.

Federal prosecutors said he had been planning since October to support the efforts of ISIL, a group designated by the US State Department as a terrorist organisation.

Emerging from the Sunni insurgency in neighbouring Iraq, ISIL has attracted many foreign fighters to its ranks, and has seized several areas in Syria, but its actions have drawn the ire of the leadership of al-Qaeda with the "general command" severing ties with the group.

Source: Agencies