OAKLAND (CBS SF) — Police activity in the vicinity of the 12th Street overpass above Interstate 980 in Oakland caused a traffic backup in both directions of the freeway for over two hours Thursday evening.

Preliminary reports indicated that a person was seen on the overpass and that police crisis negotiators were dispatched around 5 p.m.

Traffic alerts for both directions of I-980 were issued around 7 p.m. and an all-clear was sent at 9 p.m.