A pro-Ukrainian Belarusian online intelligence Telegram channel, Belaruski Hayun, says it has spotted substantial movement of Russian armed forces equipment by train across Belarus on Sunday.
It says trains loaded with military equipment have been seen at railway stations in the capital Minsk and also south-eastern Belarus.
Trucks and tanks were also seen on a train at Rechytsa railway station in the south east. Anti-aircraft missile systems and amphibious armoured vehicles were spotted waiting to be loaded nearby.
Six fighter jets and transport aircraft took off from an airfield in the west of Belarus and several Russian helicopters took off near Minsk.
The Belarusian President Alexander Lukashenko has been an ally of Russian President Vladimir Putin throughout the Ukraine war.
Russia has pulled troops away from Kyiv and is shifting most of the focus of its war to eastern Ukraine.
