SOFIA (REUTER) - British foreign secretary Malcolm Rifkind said on Wednesday the expansion of the European Union to bring in east European countries was the main challenge for the 15-nation bloc. "The United Kingdom strongly supports the enlargement of the European Union to include the new democracies of central and Eastern Europe," he told a news conference at the end of a visit to Bulgaria. "That is the single most important challenge facing the EU, even more important than many of the other matters that currently preoccupy it." Enlargement of the European Union is not expected before the end of the decade, after the 1999 target date for monetary union, an issue on which the British government is lukewarm. Rifkind said EU members should give more access to eastern European countries` agricultural and industrial exports to help them develop their economies and integrate more easily into the European Union`s single market. "When member states of the European Union refuse even modest increases in exports such as Bulgarian strawberry jam or Polish cabbages, it does discredit to the European Union and it makes it more difficult to achieve the enlargement which all countries say that they seek," Rifkind said. Bulgaria has an association agreement with the European Union and has applied for full membership, but the country is in a profound political and economic crisis and will not be among the first to join. Hungary, the Czech Republic and Poland are seen as the leading candidates to be the first new members of the EU, with others including Slovenia and Slovakia also eager to join. Rifkind arrived in Bulgaria from Romania, where he gave the same message of support for European enlargement.