MIAMI (Reuters) - A United States Federal Bureau of Investigation (FBI) agent shot and killed a Florida man with suspected links to the Boston Marathon bombings early on Wednesday, NBC News reported.

NBC said the suspect was being questioned and was originally cooperative, but was fatally shot after attacking the agent.

The Orlando Sentinel said a friend had identified the dead man as Mr Ibragim Todashev, 27, of Orlando. The newspaper quoted the friend, Mr Khusn Taramiv, as saying that Mr Todashev was being investigated as part of the Boston bombings and knew bombing suspect Tamerlan Tsarnaev because both were mixed martial-arts fighters.

Reuters could not immediately reach the FBI for comment.

FBI spokesman Dave Couvertier told the Sentinel that "the agent encountered the suspect while conducting official duties", but did not confirm the dead man's identify nor any link to the Boston bombings.

Tsarnaev, 26, died in a gunfight with the police. His brother Dzhokhar Tsarnaev was found hiding in a boat in Watertown, Massachusetts, four days after the April 15 blasts, which killed three people and injured 264 others at the finish line of the Boston Marathon.

Dzhokhar Tsarnaev, 19, was shot in the throat before his capture and is being held in a prison hospital west of Boston.

He faces charges that could carry the death penalty if he is convicted.