Japanese rescuers found five charred bodies and a trucker was pronounced dead after being pulled from his vehicle following the collapse of a highway tunnel yesterday, which crushed cars and triggered a blaze.

At least three vehicles – including a car, a truck and a wagon – were buried when concrete panels came crashing down inside the nearly five-kilometre-long tunnel, police said, according to Jiji Press news agency.

Witnesses spoke of terrifying scenes as at least one vehicle burst into flames, sending out clouds of blinding, acrid smoke. For several hours rescuers were forced to suspend their efforts to reach those believed trapped under the more than one-tonne concrete ceiling panels that crashed from the roof as engineers warned more debris could fall.

Emergency crews who rushed to the Sasago tunnel on the Chuo Expressway, 80 kilometres west of the capital, were hampered by thick smoke billowing from the entrance.

Dozens of people abandoned their vehicles on the Tokyo-bound section of carriageway and ran for one of the emergency exits or for the mouth, where they huddled in bitter winter weather.

Emergency workers equipped with breathing apparatus battled around a third of the way into the tunnel, where they found 110 metres of concrete panels had come crashing down, crushing several vehicles.

Hours after the collapse, engineers warned the structure could be unstable, forcing rescuers to halt their work as a team of experts assessed the danger.

It was during this inspection that accompanying police officers confirmed the first deaths.

“What we found resembled bodies inside a vehicle, they were blackened. We have visually confirmed them but have yet to take them out for closer examination,” an official said.