NAGOYA - The Port of Nagoya, Japan's largest port by total cargo throughput and responsible for handling some of Toyota Motor Corp.'s car exports, has suffered a crippling system glitch, with the port operator saying Wednesday it suspects a cyberattack.

As of noon, the port in central Japan remained unable to load and unload containers from trailers. Police have launched an investigation, saying the operator has received a ransom demand in exchange for the recovery of its system.

The system failure occurred Tuesday morning when an employee could not start a computer, according to Nagoya Port Authority.

A message indicating that the computer system had been infected with ransomware was somehow sent to a printer, a source familiar with the case said.

Ransomware is malware that encrypts data and demands payment in exchange for restoring access.

The operator said it intends to resume operations on Thursday morning.

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