External Affairs Minister Sushma Swaraj has expressed pain over the killing of an Indian-origin businessman killed in South Carolina in the US.

"I am pained to hear about the killing of Harnish Patel, a US national of Indian origin in Lancaster, South Carolina," Sushma Swaraj tweeted.

"Our Consul has reached Lancaster and met the family of Patel," she said. "My heartfelt condolences to the bereaved family."

Patel, 43, had closed his shop at 11.24 p.m. on Thursday. Just 10 minutes later, he was shot dead outside his home in Lancaster.

Patel's death came two days after President Donald Trump said the US condemned as "hate and evil" the killing of Indian Srinivas Kuchibhotla, who was shot dead at a pub on February 22 in Kansas by a white man who screamed, "Get out of my country".

In another incident, a Sikh man was injured when a masked gunman opened fire at him in front of his house in Kent city in Washington after telling him "Go back to your own country".

The victim, hit in the arm, survived the Friday night attack.