One of three men arrested and accused of plotting to travel to Syria to join the Islamic State (IS) terror group and wage war against the US spoke of shooting President Barack Obama or planting a bomb on Coney Island, authorities have said.

Akhror Saidakhmetov was arrested at Kennedy Airport, where he was attempting to board a flight to Istanbul, Turkey, and Abdurasul Hasanovich Juraboev, who had a ticket to travel there next month, was arrested in Brooklyn, federal prosecutors said.

The two were remanded in custody after a brief court appearance in New York.

A third defendant, Abror Habibov, is accused of helping fund Saidakhmetov's efforts and was remanded in custody in Florida.

The three are charged with attempt and conspiracy to provide material support to a terrorist organisation. If convicted, each faces a maximum of 15 years in prison.

"This is real," said New York Police Department commissioner William Bratton. "This is the concern about the lone wolf, inspired to act without ever going to the Mideast."

The US Justice Department has charged about 20 people in the past year with planning to travel to the Middle East to fight alongside militants like IS. Authorities have been concerned about Americans going overseas to train with these groups and returning with plots to carry out attacks at home.