- Fire department: A section of the concrete collapses
- The cause of the collapse is not clear, nor is the number of people potentially affected
- The tunnel is about 80 kilometers (50 miles) west of Tokyo
Tokyo (CNN) -- At least two cars were trapped early Sunday after a tunnel collapsed about 80 kilometers (50 miles) west of Tokyo, authorities said.
A 50- to 60-meter-long section of concrete fell, according to the East Yamanashi Fire Department. The swath of concrete was about 20 centimeters (8 inches) thick.
The cause of the collapse was not immediately clear, nor was the number of people potentially affected.
The Sasago tunnel is on the Chuo Expressway. The cave-in occurred on the Tokyo-bound lanes, Otsuki police said.
The road was temporarily closed, and authorities were working to rescue victims, police said.
Japanese public broadcaster NHK aired images from the tunnel, showing smoke rising and a blue car with its side smashed in. Emergency vehicles were on scene.
A journalist from NHK was driving through the tunnel at the time of the collapse. He told the broadcaster his car was damaged, but he was able to make it out unhurt.
CNN's Alex Zolbert contributed to this report.
