Russian President Vladimir Putin has congratulated Bulgaria's President-elect Rumen Radev on his victory in the vote on Sunday.
"The head of the Russian state has marked a significant potential for further development of Russian-Bulgarian relations based on the centuries-long traditions of friendship, of cultural and spiritual proximity," the Kremlin's website quotes Putin as saying.
President-elect Rumen Radev "struck a chord with voters by attacking the status quo and stressing issues like national security and migration," AFP agency writes after the presidential vote on Sunday.
It compares him with "other anti-establishment politicians" and dubs him "Russophile" in the headline and later "seen as more sympathetic to Russia".
Bulgarian President-elect Rumen Radev has gained support from the vast majority of UK- and US-based voters, official data shows.
With 94.77% of ballot protocols outside Bulgaria having been processed, Radev has won 52.04% of the overall expat vote, while his opponent Tsetska Tsacheva has received some 43.75%, the Central Election Committee (CEC) says.
Bulgarian President Rosen Plevneliev and President-elect Rumen Radev are set to meet in Sofia on Monday, officials say.
Plevneliev is receiving Radev at the Presidency less than 24 hours after exit polls suggested the latter was overwhelmingly winning the presidential race and would become the next head of state.
Rumen Radev is nearly 23% ahead of Tsetska Tsacheva in the race to become Bulgaria's next President, partial official results confirm.
With more than 99.33% of the vote counted, the socialist-backed candidate gets 59.35% support. This largely confirms exit poll data which on Sunday evening pointed to Radev as Bulgaria's President-elect.