The National Association of Home Builders called a group suspected of torching three luxury model homes Monday in Woodinville, Wash., “radical and violent.”

The group, Earth Liberation Front, which opposes commercial developments it believes are harming the environment, claimed responsibility for placing explosive devices in five houses that were erected as part of a sustainable-building development. According to published reports, the houses featured energy-efficient appliances, nontoxic paint and recycled materials.

Firefighters were able to save two of the homes from the flames.

This was the first action linked to the ELF in at least two years, officials with the FBI said. It considers the U.S.-based group terrorists. It has claimed responsibility for arson fires across the country in the last decade.

NAHB President Sandy Dunn said the group does nothing to protect the environment it claims to love.

“ELF's heinous crimes do nothing to further the cause of environmentally sensitive home building, and everything to degrade ELF's own image in the public eye as a group of violent thugs who seek to damage and destroy property and put human lives in danger,” Dunn said. “NAHB supports the continued efforts of both local and federal law enforcement in bringing these criminals to justice and putting an end to ELF's unlawful and violent activities.”