Officials inspect Japanese tunnels after collapse

The burnt wreckage of a minivan, which was crushed and caught fire in Sunday's accident, is moved on a transporter out of the Sasago Tunnel on the Chuo Expressway in Koshu, Yamanashi Prefecture, central Japan, early Monday, Dec. 3, 2012. Concrete ceiling panels fell onto moving vehicles deep inside the tunnel, and authorities confirmed nine deaths before suspending rescue work Monday while the roof was being reinforced to prevent more collapses. / AP Photo/Kyodo News

TOKYO Japanese officials are inspecting many of the tunnels across the country in light of the recent highway tunnel collapse that has left at least nine dead.

Concrete ceiling panels collapse inside the Sasago Tunnel on the Chuo Expressway in Koshu, Yamanashi Prefecture, central Japan, on Dec. 2, 2012.

/ AP Photo/Kyodo News

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Highway tunnel collapses, kills at least 9

The nine deceased were traveling in three separate vehicles inside the 3-mile long Sasago tunnel about 50 miles west of Tokyo when concrete ceiling panels suddenly began to fall on the vehicles below on Sunday morning. Two other victims were sent to the hospital for injuries.

Two vehicles also caught fire, and initial recovery efforts were slowed due to heavy smoke. Efforts have since been suspended while the ceiling is shored up to prevent more pieces from falling in the.

There are 49 other tunnels around the country that are either on highways or roads managed by the central government.

Japanese officials say the location of the accident about half-way through the tunnel has also made work difficult. The tunnel in the other direction is also closed.

According to the Wall Street Journal, about 270 one ton concrete slabs fell over a 360-foot part of the tunnel.

People who were in the tunnel at the time of the incident and were able to get out said that drivers were going the wrong way on the road trying to escape, the Guardian reported. Many people cried for help underneath the rubble. One man said that he was so frightened he abandoned his car and walked one hour to get out of the tunnel.

• Nine dead in Japan highway tunnel collapse

Ryoichi Yoshizawa , a spokesman for Central Japan Expressway Company or NEXCO-Central, told CNN that "anchor bolts" used to hold the concrete slabs to the tunnel ceiling may be to blame. He added the weathered of the bolts or concrete slabs could have contributed to the accident. While visual checks were regularly performed, there had not been a physical check of the bolts for quite some time.

"There were parts of concrete (slabs) where bolts had fallen off," Yoshizawa said.

Another possible explanation is that the recent 4.9 Tokyo earthquake on Nov. 24 may have loosened the foundation and structure of the tunnel, the Guardian reports.

Authorities say it's not clear if there are other survivors but work is slated to resume later in the day.