When Soviet occupied the Baltic States in July 1940 it also took over the aircraft used by these countries. Among the aircraft were around 20 Gladiators from the Latvian Air Force and 12 from the Lithuanian Air Force.

Five Latvian Gladiators were stored at Krustpils while the rest were dispersed at various airfields around the country at the time of the occupation. The aircraft of the Latvian Air Force were taken over by the Red Air Force and used in the training role. Subsequently they were repainted in Russian markings.

Twelve Lithuanian Gladiators were found but two of them were in need of repair.
In collaboration with the Red Army the 29th Territorial Army Corps was formed in Lithuania in the autumn of 1940. This unit possessed its own air component, the Tautine eskadrilia, which was equipped with 9 ANBO-41 and 3 ANBO-51. This unit also operated a few Gladiators. The Tautine eskadrilia was under the command of Maj. J. Kowas and based at Pluonija near Ukmerge.

During the German invasion of Russia the Tauine eskadrilia operated for a few days against the advancing German Army. As a result of heavy raids most of the Lithuanian Air Force was destroyed on the ground although a few Lithuanian Gladiators were captured intact at Schaulen airfield and sent to Germany and Langendiebach in 1942. The majority of the ex-Latvian Gladiators was captured intact at Krustpils. A few were destroyed during a bombing raid but the precise number is not known.

Source:
Gloster Gladiator Home Page - Alexander Crawford.
Iron Cross Gladiators: The Story of the Gloster's Luftwaffe Service - Andrew Thomas & Peter Green kindly provided by Andrew Thomas.
The Gloster Gladiator - Francis K. Mason, 1964 Macdonald & Co. Ltd. London
Additional information kindly provided by Yuriy Svoyskiy.