John Bacon, and William M. Welch

USA TODAY

LOS ANGELES — Fire officials suspect a massive blaze that destroyed a downtown apartment complex under construction may have been deliberately set.

"Certainly one of the things we lean toward is 'was it intentionally set?'" Los Angeles Fire Department Deputy Chief Joseph Castro said at a news conference Monday.

The cause of the fire that took up an entire city block was under investigation as a possible criminal act. "There may have been some foul play,'' fire Capt. Jaime Moore told Los Angeles Times .

Dogs trained to sniff for accelerant were on the scene as part of the investigation into the fire, which burned quickly through the building's wooden frame.

Some 250 firefighters battled the blaze, which broke out about 1:20 a.m. PT and could be seen for miles. It created traffic problems that lasted through the morning commute.

"This is a historic fire, what we as firefighters would call a career fire. It's huge," Fire Department spokesman David Ortiz told NBC News. "I really can't remember a building fire this big and I have been with the department for 13 years."

The intense heat of the blaze melted nearby highway signs and damaged nearby buildings.

The Los Angeles Department of Water and Power said its headquarters buildings saw at least 160 large window panes, 10 feet tall by4 feet wide, cracked by the heat. A 15-story county health department building suffered heat damage as well.

The fire, which shut sections of the 110 and 101 freeways, was being fed by wood framing at a planned seven-story, 1.3 million-square-foot luxury apartment complex.

The 101 Freeway reopened after several hours. The 110 southbound reopened about the same time, but northbound remained closed "due to possible burned framing collapsing onto freeway," the department said on its Twitter account. Morning rush traffic backed up for miles; northbound 110 finally was partially reopened early afternoon.

There were no reports of serious injuries.

It was one of two destructive early morning fires in the city. The other heavily damaged a commercial building in the Westlake section several miles away. Fire officials said there was no indication the fires were connected.

The 245-unit DaVinci apartment complex is billed on its website as providing a "world-class resort apartment home." Construction has been underway for more than two years. Ortiz said the structure appeared to be "completely lost."

It is one of several large and controversial downtown residential developments built in a faux Italianate style by developer Geoff Palmer.

"We understand that the cause of the fire is under investigation and we defer all such questions regarding cause directly to the LAFD,'' Palmer said in a statement to CBSLA.com.

He said a separate building, part of the same complex, would open to residents as scheduled in January.

Fire arson teams and investigators with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene.

"Experience urban-style elegance and European living in the heart of downtown Los Angeles," the apartment project's website says. "The Da Vinci, the newest member of the Renaissance collection, will offer 15 unique floor plans to match your lifestyle. Indulge in world-class amenities, such as a state of the art fitness facility, a full size indoor basketball court, a residential lounge, a library, a theater and a business center."