SOFIA (Reuters) - Bulgaria's center GERB party has a narrow lead over main political rivals, the Socialists, a few months before an early parliamentary election, Gallup International said in the first opinion poll since the presidential vote last month.


The Balkan country, which has been in political limbo, faces early polls next spring after center Prime Minister Boiko Borisov resigned following the victory of Rumen Radev, a Russia-friendly candidate backed by the opposition Socialists, in the presidential election on Nov. 13.


Some 20.3 percent of people planning to vote will support GERB while the Socialist Party scored 18.4 percent, the poll conducted between Dec 19 and 21, showed.


"The data are obviously influenced by the presidential election," Gallup said in a statement.


GERB won comfortably the parliamentary election in 2014 on promises for immediate push for reforms to spur economic growth and lure investment, collecting 32.7 percent of the votes against 15.4 percent for the Socialists.


The pollster said five political parties are likely to form the next parliament, including nationalist formation United Patriots (10.1 percent), the ethnic-Turkish Movement for Rights and Freedoms (6.3 percent) and a party, led by local businessman Veselin Mareshki (5.2 percent).

Radev takes office in January after talks to form a new government failed on Tuesday.

The center government of Prime Minister Borisov will stay in office until a new interim government is appointed.

(Reporting by Angel Krasimirov; Editing by Toby Chopra)