"It was an attack on the values of America itself," US Attorney General Eric Holder said while addressing hundreds of people gathered at a high school gymnasium in Wisconsin to pay their final respects to the six Sikhs gunned down by a white supremacist.
"And that is precisely what happened here: an act of terrorism; an act of hatred; a crime that is anathema to the founding principles of our nation and to who we are as a people," Holder said.
Holder had been deputed by US President Barack Obama to attend the memorial.
Wade Michael Page, 40, an ex-army veteran, went on a shooting spree killing six Sikhs and injuring three others, including a police officer, at the Gurdwara here on Sunday before dying of a self-inflicted gun shot wound.
"This is wrong. It is unacceptable. And it will not be tolerated," Holder said as he recollected the sacrifices of the those killed in this shootout incident.
In recent years, he said too many Sikhs have been victimised because of their look.
"Unfortunately, for the Sikh community, this sort of violence has become all too common in recent years," Holder said referring to the tragic shootout incident of Sunday, which he said was against the basic fabric of the nation.
"In the recent past, too many Sikhs have been targeted and victimised simply because of who they are, how they look, and what they believe," he said and asked Americans to discuss on how to change the hearts of those so filled with hate that the despicable act. We must ask necessary questions of ourselves: what kind of nation do we truly want to have? Will we muster the courage to demand more of those who lead us and, just as importantly, of ourselves? What will we do to prevent that which has brought us here today from occurring in the future," he asked.
"We should sensibly discuss if there is a need to change our laws, and we should certainly discuss how we might change the hearts of those so filled with hate that the despicable act we mourn today could ever have occurred. For our nation's law enforcement community, our resolve to prevent acts of terrorism and combat crimes motivated by hatred has never been stronger," he said.
Praising the contribution of the Sikhs in America's development, Holder said these were the early immigrants who came to the West Coast in the late 19th and early 20th centuries to work in lumber mills, on railway lines, and as agricultural labourers, and who stayed, building and strengthening communities around the country, from Yuba City to New York City, from Miami to Milwaukee, to Washington, DC.
Holder said it is worth remembering that, later this year, the US will commemorate the 100th anniversary of the first gurdwara in the United States.