Vote-buying and other abuses are possible in the last days of the presidential campaign, mostly at local level, said Yanitsa Petkova of the Myara polling agency.

She said turnout is expected to be low. "Bulgarians do not seem to see a huge stake in this election, and the main stake is for the parties," Petkova said.

When turnout is weak, mostly the hard-core supporters of the parties go to the polls, she explained. A presidential campaign differs from a parliamentary one, and even more from a local election campaign, because people vote for one person at national level.

Petkova thinks the dialogue between the candidates sounds more civil than usual. There will be no debate between the main candidates before the first round.

A debate is possible after the first round, ahead of a possible runoff. Petkova expects the campaign to pick up then, with everyone putting in their full effort.