Police and firefighters in the German city of Hamburg warned local residents of possible toxins in the air after fires broke out in several warehouses early Sunday morning, Reuters and News.ro reported.

Authorities said the fire started around 4 a.m. in Rothenburgsort, just a few kilometers southeast of downtown Hamburg, and that a cloud of smoke was moving toward the city center.

Several police officers, firefighters and other emergency personnel were at the scene when a thick cloud of dark smoke rose. The sky has darkened, the weather is gloomy.

About 140 people have been evacuated and it is not yet possible to say exactly how dangerous the situation is, a police spokesman said.

A fire official said the threat level had been lowered, although the fire was still burning at midday, but people should stay indoors with windows closed.