Incumbent Georgi Parvanov has won the first round of Bulgaria's presidential election but faces a run-off because of low turnout, official results show.
Mr Parvanov (L) and Mr Siderov will run again next Sunday
With almost all the ballots counted, the socialist leader has more than 60% of the vote, compared with ultra-nationalist Volen Siderov's 22%.
But with turnout short of the 50% mark, the two men will run again next Sunday.
If Mr Parvanov wins, he will be the first Bulgarian president to win a second term.
"This is a good basis for achieving final victory in a week's time," he told journalists.
"Support for us is support for our policy of unifying the nation," he said.
The presidency is largely a figurehead position, as power lies with the prime minister.
But the 49-year-old historian is respected for his efforts to raise Bulgaria's international profile ahead of Nato and EU membership.
Mr Siderov, 50, is a populist figure who has hit out at minority groups and attacked the government over privatisation deals.
The low turnout was blamed on poverty among large segments of the population and unhappiness over the government's economic and social reforms.
These concerns have helped Mr Siderov and his nationalists, the BBC's Nick Thorpe says.
But on paper at least Mr Parvanov looks set to win the election next Sunday, our correspondent adds.
Full official results from the first round should be released on Monday or Tuesday.