An Indian-origin man was killed and another injured by a former Navy serviceman who mistook them for "Middle Easterners", officials said.

The man also shot and injured a non-Indian American who is hailed as a hero as he tried to protect the two during the attack on Wednesday night in Olathe, Kansas State.

Srinivas Kuchibhotla died and Alok Madasani was injured when Adam W. Purinton shot them at a bar after telling them "get out of my country", media quoted a witness as saying.

The Hindu American Foundation's (HAF) called the attacks a hate crime. But officials had not classified it a hate crime as of Thursday night, saying they were investigating the angle.

Ian Grillot, 24, who came to their rescue, and Madasani were in hospital recovering from their injuries.

Purinton was arrested in Clinton city of neighbouring Missouri state when a bartender reported to police about him saying that he had killed "two Middle Eastern men", according to local police.

"It was a tragic and senseless act of violence," Olathe Police chief Steven Menke said.

According to his profile on LinkedIn, Kuchibhotla, 32, graduated from the Jawaharlal Nehru Technological University in Hyderabad in 2005 with an electrical engineering degree.

He received a master's degree from the University of Texas in El Paso and was working as an aviation programmes manager with Garmin, an electronics manufacturer best known for its consumer navigation systems.  

The manager at Rockwell Collins, Kuchibhotla's former employer, Rod Larson, told the Star: "He was very sharp. A top-of-his-class kind of guy. His personality was exceptional."

Madasani, 32, was a graduate of the Vasavi College of Engineering in Hyderabad. He was also a manager at Garmin.

The HAF condemned the attacks describing the killings as "the first reported bias-motivated fatality in the US after the bitter presidential election".

"We call upon the US Department of Justice and local law enforcement to investigate this murder as what it is, a hate crime," Jay Kansara, HAF's Director of Government Relations, said.

"Anything less will be an injustice to the victims and their families."

Federal officials on Thursday joined local public prosecutor Steve Howe when he charged Purinton with pre-meditated and attempted murder.

According to The Star, federal officials said they were investigating to determine if the attack bias-motivated hate crime.

The Star reported that acting federal prosecutor for Kansas, Tom Beall, said his office would be evaluating the case and "there will probably be more to come later from us".