Prime Minister Manmohan Singh said on Monday he was "deeply shocked and saddened" by the killings of at least six people at a Sikh temple in the United States.
"That this senseless act of violence should be targeted at a place of religious worship is particularly painful," Singh, a Sikh himself, said in a statement.
"I am deeply shocked and saddened," Singh said, adding that India stood "in solidarity with all the peace-loving Americans" who have condemned the attack.
"We hope that the authorities will reach out to the grieving families and ensure conditions that such violent acts are not repeated in the future," he added.
A gunman attacked worshippers on Sunday at a suburban Sikh temple in Wisconsin in the midwestern United States, killing at least six people before he was shot dead by police.