The push-backs occurred in the districts of Vilnius and Salcininkai.
In Vilnius district, border guards' stationary video surveillance cameras and a mobile phone recorded an attempt by Belarusian officers to stage mock testimonies of alleged beatings of migrants, VSAT said.
"There is no doubt that such material would be disseminated through the neighboring country's propaganda channels," it said.
Lithuania's border guards saw several dozen signal flares launched on Belarus' territory at nighttime, according to the service.
VSAT and the military have stepped up border patrols.
Over 4,100 migrants have crossed into Lithuania from Belarus illegally so far this year.
Lithuania has declared a state-level extreme situation over the irregular migration influx which it says is being orchestrated by the Belarusian regime.