Russia may raise tariffs on Bulgarian exports unless the Balkan country lowers customs duties on industrial imports from Russia, a trade official said on Friday, in reports from Associated Press.

AP quoted Russia's trade representative in Bulgaria, Alexander Semernev, as saying that Sofia failed to fairly respond to partial trade incentives that Russia has offered it. But he would not elaborate on those incentives.

Semernev reportedly said that Bulgaria levied tariffs of between 13 and 25% on Russian tractors, cars and trucks, while duties on similar products from the European Union were between 0 and 7.5%. He said his country's goods were being "discriminated against.''

"Liberalisation of trade is a two-way issue, a road with two lanes,'' Semernev reportedly said in an interview for the private Darik radio. "We are considering an option of raising tariffs and cancelling incentives for Bulgaria.''

"Russia is dissatisfied by the moves of the Bulgarian government,'' Semernev said. "We meant that Bulgaria should revise import tariffs on machines and technical products from Russia, but nothing was done in recent years.''

AP said that Bulgaria has started accession talks with the EU in March and will gradually liberalize trade with the union. The Balkan country has also revamped its tariff policies on motor vehicle imports in line with EU environmental standards which Russian cars don't match, encouraging the use of unleaded fuels.