Howard County public schools will continue operating under a modified lockdown through tomorrow, which means all exterior doors will be locked and all outdoor activities canceled or kept indoors. Field trips, work study programs and mentorships are called off.

"[The Howard County police] are on high-alert," said school spokeswoman Patti Caplan. "It's a real eye-opener. They're concerned, and we're following their lead."

Schools Superintendent John R. O'Rourke will decide day-to-day whether after-school activities and evening meetings will go on as scheduled.

An announcement is expected by 10 a.m. about this afternoon's events.

Columbia Association and Department of Recreation and Parks after-care programs will be held as usual.

For updates: Howard County Public Schools system's information office, 410-313-6682, or www.howard.k12.md.us.