Are Russia's threats to invade Nato's Suwalki Corridor with Wagner troops a serious risk?

Russia has threatened to use its Wagner private army to invade Nato's "weakest link" in Poland and Lithuania - a move that would likely trigger a Third World War.
A top Putin parliamentarian claimed on state television the mercenary group is ready to strike in "a matter of hours" from Belarus.
The Suwalki Corridor - or Gap - is a 60-mile strip of land straddling the border between Poland and Lithuania.
Rear Admiral Dr Chris Parry a Strategic Forecaster and Defence Analyst gives his views on whether the threats for Putin's MP is a serious risk to NATO or nothing more that empty threats.