According to the Report, this is reported by the German media.
Several airport employees were injured and are currently receiving medical attention.
Airport operator Fraport confirmed the "incident" without providing additional information.
The airline noted that a crisis group has been set up to study the incident.
"Several employees have been injured and are currently receiving medical attention," Lufthansa said in a statement.
The flight crew was already on board at the time of the incident, but there were no passengers yet.
