A pair of huge fires that broke out in downtown Los Angeles, damaging four buildings and shutting highways during the busy morning commute, have been brought under control.

No injuries were reported in Monday's blaze but the flames near a major traffic junction could be seen for miles and billowing clouds of smoke closed down adjacent highways in two directions.

The fire was in a building planned to be a tall residential structure, David Ortiz, Los Angeles Fire Department public information officer, said, adding that he did not think anyone was living or working there.

Los Angeles' Route 101 was closed in both directions, while the California Highway Patrol said transition lanes between Routes 110 and 101 were shut down.

City fire officials were unable to give an immediate cause for the blaze, which severely damaged a seven-storey apartment building that was under construction.

Damage to the structure appeared to be nearly total.

Flames spread for a whole city block, nearly a million square feet, officials said.

The apartment development in the city's business district had caused some controversy in the community due to a pedestrian bridge the developers wanted to erect so residents could avoid street traffic, the Los Angeles Times newspaper reported.

Scaffolding fears

The blaze spread quickly through the building and officials warned there was a risk of building scaffolding falling into the roadway even after the fire was contained.

The fire was so big that responding firefighters could feel the heat from the flames from their fire station, a city information officer told AFP.

Two adjacent office towers were also damaged by the extreme heat. Flames spread to the buildings but were extinguished, officials said.

A second fire a short drive away also caused severe damage to a building housing apartments and commercial spaces that was under renovation.

Both fires were brought under control after several hours.

More than 350 firefighters - a quarter of the city's firefighting force - battled the blazes, the fire department's Ortiz told AFP.

Firefighters from nearby areas came in to assist with the response efforts.

Source: Agencies