SAN DIEGO -- Federal agents are investigating the possibility that eco-terrorists are behind Friday morning's large fire that leveled an apartment complex under construction in University City, 10News reported.

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See Images Of Flames Eco-Terrorism To Blame For Massive Fire?

No injuries were reported as a result of the fire, which broke out at about 3 a.m. at the intersection of La Jolla Village Drive and Towne Centre Drive. It caused more than $20 million in damage.

A large banner near the fire read, "If You Build It, We Will Burn It -- ELF." Investigators believe ELF could stand for the Earth Liberation Front -- an eco-terrorist group responsible for numerous construction site fires worldwide.

FBI agents, Alcohol, Tobacco and Fire Arms agents, and the Metro Arson Strike Team are investigating.

Before burning itself out, the fire shot flames as high as 500 feet into the predawn sky, engulfed what was to have been a 200-unit building and caused a 100-foot-high crane to topple, according to 10News.

Fire officials said that the heat from he blaze was so intense that window blinds from inside an apartment complex 500 feet away melted.

"It broke windows from the radiant heat. We can only spray water 200 feet, so we couldn't even get close enough to get any water on the fire," Division Chief Bruce Cartelli said.

About 500 nearby residents were evacuated.

"The original fire alarm went off probably a little bit after 3 a.m. Then, the police department started banging on doors and started evacuating the entire complex," evacuee Jonathan Rose said.

"When we came outside and I saw the flames and the smoke and heard people screaming. It was pretty scary," evacuee LaRae Steinmetz.

The ELF is considered to be one of the most domesticated terrorist groups in the United States. Its claimed responsibility for 600 fires at construction sites since 1996, causing over $100 million in damages.