An electrial problem forced the city to close the Armstrong Tunnels in both directions this morning, and it's unknown when they will reopen.

City public works officials said the cause of the problem was unknown, and Duquesne Light crews are on the scene trying to discover it. The problem has knocked out lights and ventilation in the tunnels, which connect Second Avenue and Forbes Avenue, Uptown.

Electrical problems were also reported at the tunnels at the start of rush hour last night, and city police had to direct traffic.