At least five people were reported trapped inside this Japanese road tunnel when it caved in.
Japanese media said at least three cars were stranded inside the Sasago tunnel between Otsuki and Koshu city west of Tokyo, and that one had caught fire.
About 100 metres of the tunnel caved in.
Rescue teams are on the scene but smoke was causing some problems.
The 4.3 kilometre-tunnel is the second longest on Japan's Chuo expressway.
Japan tunnel collapses (0:34)
Dec 2 - Several reported trapped as a road tunnel collapses west of Tokyo. Paul Chapman reports. ( Transcript )