The transport ministry on Tuesday informed the operator involved in a fatal bus crash last month that its license to run a tour bus business will be revoked after it was found to have committed several safety regulation breaches.

The penalty that Tokyo-based ESP faces is the strictest administrative disciplinary action that the transport ministry can take. The ski tour bus operated by the company careened off a road in Nagano Prefecture on Jan. 15, killing 15 people on board.

"We urge (the company) to take this seriously and express remorse (over the accident)," Land, Infrastructure, Transport and Tourism Minister Keiichi Ishii said at a news conference.

After conducting a special inspection of the company following the fatal crash, the ministry found that ESP had failed to ensure that the bus drivers involved in the accident received regular health checkups.