Police were responding to a hazmat situation at a downtown Chicago building Tuesday afternoon.

Seven to 10 propane tanks were discovered on the fourth floor of a building in the 100 block of North Clark Street, according to Chicago Police News Affairs.

The Chicago Fire Department said the propane tanks were located in a minivan inside a parking garage. They could not say how many tanks were located but said the situation was "secure" as of 12:15 p.m.

Clark Street was closed off in the area as authorities continued to investigate.

The Chicago Transit Authority also said Blue Line and Loop "L" trains were not stopping at the Clark/Lake station due to police activity. The no. 22 Clark and no. 24 Wentworth busses were also temporarily rerouted via Clark, Wacker, LaSalle and Washington.

Check back for more on this developing situation.