CNN
 — 

Residents in the German city of Hamburg have been warned of heavy smoke and possible toxins in the air after a major fire broke out at a warehouse.

Video circulating on social media shows the warehouse engulfed in flames early Sunday morning, with smoke billowing into the sky.

“Smoke gases and chemical components in the air caused by a warehouse fire can affect breathing. The cloud of smoke is moving towards the city center!” an alert from the Hamburg fire department said.

Some 140 people have been evacuated, a police spokesperson said, according to Reuters.

According to local news outlet NDR, local residents have been instructed to close their windows and doors.

“The inner city of Hamburg has gone completely dark,” a fire department spokesperson said, as quoted by the outlet.

It is not clear yet what caused the fire.