Updated, 12:15 p.m.
Katonah Lewisboro schools has cancelled the district lockout as the threat of suspicious activity in Ridgefield has been investigated and resolved.
All outdoor activities during and after school will take place as scheduled.
Katonah-Lewisboro schools announced they would be operating in "lockout" mode Monday in reaction to a potential safety risk in nearby Ridgefield schools.
As of 10:10 a.m., Ridgefield schools were in lockdown because of a report of a suspicious man sighted at the Branchville train station. Authorities have not yet uncovered any threats.
In Ridgefield, all local schools were placed in lockdown after authorities, along with a K-9 unit, were canvassing the area after receiving a report of a man with an unknown item slung over his back.
Police were first informed of the suspicious person at about 9 a.m.
K-L officials sent out a message to all families describing "lockout" procedures:
All exterior doors will be locked. Deliveries will be controlled, there will be increased supervision at arrival and dismissal, there will be no outdoor recess or PE, and extra-curricular activities may be postponed or cancelled. All visitors should be prepared to show identification. Limited entry may be imposed throughout the day. If you are in a school, please follow the directions of staff.
The incident comes three days after the Sandy Hook Elementary School shooting, in which a single gunman equipped with three firearms killed 20 children, six adults, and then himself, in Newtown.
For full coverage of the Sandy Hook tragedy, click here.