The gay pride parade in Split, Croatia, was attacked June 11.
Activists said thousands of opponents hurled rocks, bottles, firecrackers, flares, tear gas, eggs, tomatoes, glass, bricks, shoes, paint, cigarette lighters and flowerpots at the 200 marchers.
They reportedly shouted, "Kill the gays."
Up to a dozen people were injured, including some reporters.
Hundreds of police officers arrested at least 135 people and escorted the marchers away from the conflict.
Organizers faulted the authorities for failing to protect LGBT marchers' right to freedom of assembly.
"None of it would have happened if they cleared the route properly," said one participant.