A fire has broken out at a building in downtown Houston, with a witness reporting that he heard an "explosion," according to local media. Footage from the scene shows the flames billowing from the windows of the premises.

LIVE UPDATES: 'Worst flood ever' hits Houston in the wake of Hurricane Harvey

The incident occurred at offices belonging to Lone Star Legal Aid on Fannin Street, according to ABC 13.

Looks like the fire department is on the scene pic.twitter.com/cz3w0NW2XB — Chris Hisle (@cspwal) August 28, 2017

A photo posted on social media shows a fire truck battling the blaze.

Fannin and bell explosion followed by fire at law office #khou11#houstonpic.twitter.com/7tBUEWs4OG — Jason Bo (@Jasonbollo) August 28, 2017

One firefighter was injured while hosing down the blaze, KPRC reporter Haley Hernandez tweeted, adding that he had been taken to a nearby hospital.

Not what are emergency responders need but there's a fire at Fannin & Bell. One firefighter came out, got on stretcher & went to hospital pic.twitter.com/D2jCHiSFzF — Haley Hernandez (@HaleyKPRC) August 28, 2017

Hernandez said the building is next to a daycare center.

The fire has reportedly been extinguished, a senior executive producer for local news outlet KPRC 2 tweeted.

UPDATE: HFD crews on scene in 1100 Block of Bell St, Downtown. Fire appears to be out. Likely source of smoke downtown #houstonflood@KPRC2 — Aaron Wische KPRC (@AaronKPRC) August 28, 2017

Lone Star Legal Aid tweeted hours before the fire that its Houston office would be closed Monday, due to Tropical Storm Harvey.

In addition to our Angleton/Clute, Beaumont, Conroe, Houston, and Galveston offices, our Bryan office will also be closed today. — Lone Star Legal Aid (@LStarLegal) August 28, 2017

The fire comes as Houston struggles to cope with massive flooding inflicted on the city by Hurricane Harvey which has since been downgraded to a tropical storm.

As the city braces for more heavy rain and flooding in the coming days, the US Army is releasing water from two local reservoirs which have risen too quickly as a result of Harvey.

The Federal Emergency Management Agency (FEMA) has said it is working to assist people in the area, noting that 450,000 people are likely to be in need of help. More than 30,000 are expected to be placed in temporary shelters.