CTA Blue Line service disrupted by police activity in Loop

CHICAGO - Service on the CTA BLue Line was shut down Tuesday morning due to police activity in the Loop.

What we know:

Around 6 a.m., trains were standing in both directions near the Jackson station at 328 S. Dearborn St., according to the CTA.

The transit agency said "significant" delays are expected.

What we don't know:

It was not immediately clear what prompted the police response or when service will be restored.

What you can do:

Head over to the CTA's website for the latest updates.

This story is developing.