The court released a statement saying that those on trial are accused of crimes of murder, terrorism, and other crimes.
Two of the trials are being held in the towns of Yangibozor and Tuytepa, near Tashkent. Two other trials are being held in the towns of Gulistan and Yangier, both some 100 kilometers outside the capital.
The court says that the trials are being conducted behind closed doors for security reasons.
These are the latest known trials after the sentencing last month of 15 men to jail terms of up to 20 years over the Andijon events.