Police in Illinois believe radical anti-white supremacist activists were behind an attack on a restaurant in the Chicago area Saturday night.

According to witnesses, 15 to 18 young people dressed in black burst into a Tinley Park Irish restaurant with bats and hammers attacking another group of 12 to 15 people who were meeting there.  Ten were injured.

A waitress told the Chicago Tribune:

“It was the scariest … day of my life,” she said. “They took out the whole restaurant. It was absolutely horrible.”

The town’s mayor confirmed that the attackers belonged to a group called “Anti-Racist Action,” police say several of the attacked had ties to a white supremacist group.  Five people remain in police custody, charges are pending.

The restaurant’s owner told reporters that he had no idea the people dining at his establishment were racists, saying they told him that they were from an Irish heritage association.

“We had no idea who these people were,” he said. “We don’t ask for people’s political stuff when they come in the door.”