Oak Lawn police are responding to an active barricade situation Saturday in the southwest suburb.
The Oak Lawn Police Department warned residents of the situation about 10:30 a.m., tweeting they had units investigating a barricaded subject in the 10400 block of Mason Avenue. Residents of the area have been advised to stay inside and stand clear of windows and patio doors.
A large police presence has been established between 103rd and 105th Streets and Austin and Central Avenues, police said.
As of 12:40 p.m., the situation remains ongoing, police said.