Washington:
US President Barack Obama said on Monday that Americans would "recoil" if Sunday's Sikh temple shootings in Wisconsin were "motivated in some way by the ethnicity of those who were attending."
"Regardless of what we look like, where we come from, who we worship, we are all one people and we look after one another and we respect one another," the president said.
President Obama spoke to reporters in the Oval Office after he signed unrelated legislation at the White House.
Officials said on Monday that the gunman who killed six people inside the temple and was killed in a police shootout was 40-year-old army veteran Wade Michael Page.
A civil rights group identified him as a "frustrated neo-Nazi" who led a white supremacist band.
The non-profit Southern Poverty Law Centre said Page had been on the white-power music scene for more than a decade, playing in bands known as Definite Hate and End Apathy.
"We've been tracking the suspect in the Wisconsin shooting for a little more than a decade. We know that he has traversed one of the most violent parts of the white supremacist scene, namely the racist skinhead music scene," said the Southern Poverty Law Centre's Heidi Beirich.
"This world is extremely violent. Neo-Nazi skinheads have been known to murder minorities," she said.
Authorities said Page strode into the temple carrying a 9 millimetre handgun and multiple magazines of ammunition and opened fire without saying a word.
When the shooting at the Sikh Temple of Wisconsin in suburban Milwaukee ended, six victims ranging in age from 39 to 84 years old lay dead. Three others were critically wounded.
Page joined the military in Milwaukee in 1992 and was a repairman for the Hawk missile system before switching jobs to become one of the army's psychological operations specialists assigned to a battalion at Fort Bragg.
Page was demoted in June 1998 for getting drunk while on duty and going AWOL (Absence Without Official Leave), two defence officials said, speaking on condition of anonymity.
Authorities said suburban Milwaukee police had no contact with Page before Sunday's shooting, and his record gave no indication he was capable of such violence.
Beirich said this type of domestic "terrorism" is on the rise and she expects it to continue.
"We're going to see more of this kind of violence by people who simply can't handle the changing demographics," she said, referring to the increasing percentage of non-white Americans.
The FBI is leading the investigation into the attack because the shooting was considered a possible act of domestic "terrorism".
The agency said it had no reason to believe anyone other than Page was involved.