A fire broke out Monday afternoon in the concrete channel of the Los Angeles River near Chinatown.

The fire, which appeared to be burning some type of substance on the river floor, sent black smoke into the air that could be seen for miles.

The Los Angeles Fire Department said the fire burned out on its own in about 20 minutes. Because no water was used to douse the flames, officials said there was no polluted runoff into the river.

UPDATES:


6:55 p.m.: This article was updated to reflect that the fire had burned out.

This article was originally published at 6 p.m.