Bulgaria faces the challenge of being "pushed... toward a geopolitical sandwich of former empires to the east", President (2012-2017) Rosen Plevneliev said on Sunday.

Plevneliev, who left the office on January 22, told private broadcaster NOVA TV that Bulgarians should be aware of the "power of Russian propaganda".

He made it clear he was ready for a "tough" collision betweeen established parties and political newcomers in the run-up to March 26's early election.

The former President added he would challenge the actions of all those seeking to "push Bulgaria in another direction - into a geopolitical sandwich of former empires to the east," in an apparent reference to the Ottoman Empire and the Russian Empire.

He also slammed Bulgarian authorities for failing to produce a European Commissioner pick, with the Bulgarian seat having remained vacant since the beginning of January. "This is part of the perfect story, we are sending a message we don't care," he argued.

Bulgaria is "passive" and confined to its own problems and "left with its own low ambitions and inability to open doors and defend causes in Europe," while Europe is now running on two tiers, Plevneliev opined.