Firefighters are tackling a major blaze on Princes Street in Edinburgh, with crews called to the scene in the early hours of Thursday morning. According to reports, the emergency call is received at around 02:50, prompting a large response including seven fire engines and three specialist vehicles. Other coverage also places the alarm in the early hours of Thursday, indicating the incident occurs overnight into the morning. The reports describe the operation as an ongoing firefighting effort, but do not provide further confirmed details about the building affected, the cause of the fire, or any injuries at the time of publication. The incident draws attention to Princes Street, a central area of Edinburgh, and highlights the scale of the fire service deployment, including specialist units. Authorities are working at the scene as firefighters continue their response. Further information such as the precise location, extent of damage, and updates on the situation are not included in the provided summaries.