European foreign ministers have extended a visa ban on Belarus officials to include President Alexander Lukashenko and 30 others.
Mr Lukashenko has been in power since 1994
Mr Lukashenko was sworn in for a third term in office on Saturday, following his disputed on 19 March election win.
His election victory was criticised by international observers as being neither free nor fair.
The Belarus foreign ministry denounced the EU move and said it was "obliged to take adequate measures in response".
EU officials say further steps remain possible, such as a freezing of assets of the Belarussian leadership.
The visa ban means Mr Lukashenko and the 30 ministers, prosecutors and election officials cannot enter EU countries.
The list includes: Mr Lukashenko's chief of staff Gennady Nevyglas, Education Minister Alexander Radkov, Information Minister Vladimir Rusakevich, Justice Minister Viktor Golovanov, head of state television and radio Alexander Zimovski, Belarussian prosecutor-general Pyotr Miklashevich and KGB security service chief Stepan Sukhorenko.
The EU had earlier banned six Belarussian officials.
The president was returned to office for a third term with 83% of the vote, but the OSCE, Europe's main election monitoring body, said the elections were "severely flawed".
The result sparked demonstrations in October Square in the capital, Minsk, and hundreds of opposition supporters were arrested.
Mr Lukashenko has accused the West of waging a crusade to drown his country in the chaos of anarchy.
Reacting to the EU move on Monday, the foreign ministry said "the European Union and United States cannot alter the choice of the Belarussian people".
The BBC's Oana Lungescu in Brussels says foreign ministers from Central and Eastern Europe spearheaded the move to isolate the Belarus leadership.
The Slovenian Foreign Minister, Dimitrij Rupel, said the EU had to send a "strong signal" and the visa ban list would be kept open at the request of his Czech colleague.