Updated

Flames engulfed a California construction site early Friday morning, prompting evacuations in nearby apartment buildings.

The fire broke out inside the seven-story building in Oakland shortly before 4:30 a.m., KTVU reported.

The blaze quickly spread, with flames shooting out of the roof less than an hour after it began. Motion sensors inside the building picked up activity about 4:45 a.m., sources told KTVU.

Thick, black smoke was seen billowing from the site. A crane at the site was on the verge of collapsing, swaying in the fire.

Nearby apartment buildings were evacuated. There were no reported injuries.

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It's unclear how the fire started.

The site, called Alta Waverly, was a large parking lot and a small commercial building that was being constructed into a multi-use residential building.

It was slated to open in February and was expected to contain 193 residential units and 31,500 square feet of retail, according to city site plans.

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