The FBI has arrested three foreign nationals living in Brooklyn who agents say sought to join the Islamic State.

Two of the men had threatened to kill police officers and FBI agents in the US if they were unable to travel to Syria, the FBI said.

The men came to the authorities' attention after they posted to Uzbek-language websites in recent months.

In one post, they pledged to kill US President Barack Obama, the FBI said.

Abdurasul Juraboev, 24, and Abror Habibov, 30, both of Uzbekistan; and Akhror Saidakhmetov, 19, of Kazakhstan, were charged with conspiracy to provide material support to a foreign terrorist organisation.