Bulgarians to choose new president
Bulgarians are going to the polls to choose a new president who will have to face both a possible rise in migrants from neighbouring Turkey and growing tensions between Russia and the West.
For the first time, voting in the presidential election is compulsory for the Balkan nation's 6.8 million voters. Also on the ballot is a referendum on electoral process issues.
Opinion polls suggest that none of Bulgaria's 21 presidential candidates are likely to win in the first round by getting more than the required 50% of the vote, and that a presidential run-off will be held on November 13.
The front-runner is Parliament speaker, Tsetska Tsacheva, a 58-year-old lawyer and member of the governing centre-right GERB party of Prime Minister Boiko Borisov.
To become the first female president of the country of 7.2 million people, Ms Tsacheva must defeat the opposition Socialist contender Rumen Radev, 53, a former fighter pilot and Bulgarian air force chief.
If Ms Tsacheva is elected, she is widely expected to continue the pro-Europe foreign policy of incumbent Rosen Plevneliev, while her main opponent is seen as more sympathetic to Russia.
Mr Radev has repeatedly said he would comply with Bulgaria's European obligations but has called for better relations with Russia and the lifting of sanctions against Russia, arguing that "being pro-European does not mean being anti-Russian".
A recent poll by Gallup International Balkan suggests the presidential election will go to a second round, with Ms Tsacheva facing Mr Radev.
Polling stations will close at 8pm (1800 GMT) and preliminary results will be available 90 minutes later. Final results will be announced on Tuesday.