Boston ? A homeless man sleeping in a park was attacked early Sunday by two men who kicked him in the stomach and then set him on fire, police said.

No arrests were made and police gave no indication of what might have motivated the attack.

The 30-year-old homeless man, whose name was not released, told police he was awakened by the men kicking him in Langone Park in the city’s North End.

He drifted back to sleep after the assault, but the men returned, drenched him with a flammable liquid and set his legs on fire, police said.

A 911 caller reported flames in the park, and firefighters found the man wrapped in a blanket after he had ripped off some of his burning clothes.

The park is a short walk from a cluster of downtown bars.

The victim was treated at Massachusetts General Hospital for burns to his legs.

Nationally, the number of assaults against the homeless has risen dramatically since 2002, according to a recent report by the National Coalition for the Homeless. In 2005, 73 homeless people were assaulted nationwide and 13 died, the report said.