MODESTO, Calif. — Police said Monday that they are looking for two men who beat a Sikh man and spray-painted a neo-Nazi symbol on his truck in what they're calling a hate crime.

Surjit Malhi told KOVR-TV that he was putting up campaign signs for local Republicans at night when two men ambushed him, throwing sand in his eyes before beating him in the head, shoulders and neck on July 31 in Keyes, California, about 90 miles (145 kilometers) east of San Francisco.

Malhi, 50, said the men screamed at him to "go back to your country" before spray-painting the same message and a white supremacist symbol on his truck. The men were wearing black hoods and had blue eyes, he said.

"I'm American, 100 percent," Malhi said. "This is my country. If you are a real American and you love America, you should not do that. That is not the American way."

The symbol the men spray-painted on his truck is the white supremacist version of the Celtic Cross, according to the Anti-Defamation League.

Stanislaus County Sheriff Adam Christianson told The Modesto Bee that the assault is being investigated as a hate crime, saying it was "a random despicable criminal act."

Malhi said he believes the turban he was wearing saved his life during the attack because it softened the blows to his head.

"It's very scary," said Malhi, who said he has been experiencing headaches and dizzy spells since the attack.

The Sikh Coalition reported an increase in violence and discrimination against Sikh Americans after the Sept. 11, 2001, attacks, with more than 300 cases reported throughout the U.S. in just one month.

In March, the collation said there has been another "alarming recent spike" in hate crimes against Sikhs, with an estimated one a week since the beginning of 2018.

In January, two men were sentenced to three years in prison for the beating of a Sikh man in the San Francisco Bay Area. In March, a Sikh man in Seattle said a man shot him in the arm in his driveway after telling him to go back to his country.

In 2012, a man shot and killed six Sikh worshippers and wounded four others at a Sikh temple near Milwaukee before killing himself.