* Talks to form a centre-right government collapse
* Early election likely by early April
* Some analysts expect rise in pro-Russian sentiment
By Tsvetelia Tsolova
SOFIA, Dec 20 (Reuters) - Bulgaria is heading towards an early parliamentary election next spring after talks to form a new government under the mandate of a small right-wing party failed on Tuesday, officials said.
The Balkan country has been in political limbo since centre-right Prime Minister Boiko Borisov resigned last month following the victory of Rumen Radev, a Russia-friendly candidate backed by the opposition Socialists, in the presidential election.
"We could not reach a broad agreement on policies and continue to govern. The current parliament is unable to form a government and we are heading towards early elections," Tsvetan Tsvetanov, deputy chief of Borisov's GERB party, told reporters.
The political direction of the small Black Sea nation, which is a member of the European Union and NATO, is of interest to both the West and Russia, which is keen to rebuild its influence in southeast Europe as it presses for relief from international sanctions over its annexation of Ukraine's Crimea.
Bulgaria now faces months of political uncertainty and is likely to end up again with a fragmented parliament that may struggle to produce a stable coalition government, political analysts said.
Some expect a further spike in the anti-migrant sentiment as well as a softer stance towards Russia following the convincing victory of Radev, who had campaigned on a platform of tougher immigration controls and improved ties with Moscow.
"After Radev's victory, we can expect a strengthening of the populist and nationalist waves and a revision of the Bulgarian attitude towards Russia and the sanctions imposed on it," said Parvan Simeonov, analyst with Gallup International Balkans.
REFORMS DELAYED AGAIN
The right-wing Reformists, the junior partner in Borisov's outgoing government, were the only political faction to attempt to fashion a new cabinet after his resignation, but failed to convince their allies, Borisov's GERB and the nationalist Patriotic Front, to back them.
Analysts say an early election will delay much-needed reforms in the poorest EU member state but is still a better option than a government on "life support".
The Reformist Bloc will now return the mandate to Bulgaria's outgoing President Rosen Plevneliev, who will appoint an interim administration or leave that option to President-elect Radev, who takes office on Jan. 22.
Radev, a U.S.-trained former air force commander, will then have to set a date for the parliamentary election, originally scheduled for 2018 but now likely in late March or early April.
Bulgaria's president has limited executive powers but represents the nation on the global stage. Radev says he fully supports Bulgaria's membership of NATO and the EU but wants it also to improve ties with Moscow, its communist-era overlord. (Additional reporting by Angel Krasimirov; Editing by Gareth Jones)
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