The United States accused the country's authorities of trying to undermine democratic institutions.
A U.S. statement to the Organization for Security and Co-operation in Europe (OSCE), said that in recent weeks, authorities in Minsk have harassed and intimidated non-governmental organizations, opposition political figures, and civil society groups.
The U.S. spokesman, Bruce Connuck, listed a number of groups that he said had suffered harassment.
Connuck told the OSCE in Vienna that there is a "growing atmosphere of intimidation" against these targets.
The U.S. diplomat also accused the Belarus authorities of manufacturing conspiracies and crises to justify its repression.
The EU Adds Its Voice
Also today, European Union External Relations Commissioner Benita Ferrero-Waldner condemned what she called "serious violations" of the campaigning rights of the opposition candidates.
Her statement says the EU is particularly concerned by reports of the detention of Alyaksandr Kazulin, one of the four registered candidates in the race. Kazulin was held for several hours today and allegedly beaten before being released.
She also noted that a declaration adopted by EU foreign ministers in January said the EU is ready to take "further appropriate restrictive measures against the responsible individuals" if the elections are not conducted in a democratic manner.
President Lukashenka's warning came during a speech in Minsk as thousands of opposition supporters rallied in the streets of the capital against his regime.
Lukashenka said tension was rising in Belarus ahead of the vote and urged vigilance against "provocations."
(with additional agency material)
Belarus Election Preview
A protester in Vitsebsk calls for a boycott of the 19 March vote (RFE/RL)
ALL EYES ON BELARUS: No matter the outcome, the presidential election to be held on 19 March is an important event for the future of Belarus, according to three experts on the country who spoke at an RFE/RL briefing in Washington, D.C., on 14 February.
ROBIN SHEPHERD, adjunct fellow with the New European Democracies Project at the Center for Strategic and International Studies (CSIS), said that civil society has been seriously weakened in Belarus as a result of the current regime's self-isolating and corrupt policies. Shepherd believes incumbent Belarus President Alyaksandr Lukashenka has decided he needs a democratic election to legitimize his regime. Shepherd cautioned that opinion polls be read accurately when evaluating the election results when they become available. For example, he predicted that the true level of support for Lukashenka will probably be from 10 to 12 percentage points less than the actual reported vote count, because of a "fear factor" within the Belarusian electorate -- that some voters will fear that Lukashenka can determine how a person voted. Shepherd said he cannot predict the outcome of the election, but does believe the opposition could win a fair vote in Minsk.
JAN MAKSYMIUK, RFE/RL's Belarus and Ukraine regional analyst, noted several differences between Belarus on the eve of its presidential election and Ukraine just prior to its "Orange Revolution" in December 2004. He said that, in Ukraine, no incumbent was running for president, putting both candidates on a more equal footing. Unlike Ukraine, the opposition is not represented in the Belarus parliament or in local governments, Maksymiuk said. The primary opposition candidate, Alyaksandr Milinkevich, will not receive any positive media coverage due to state control of the Belarusian media, Maksymiuk said, and the relative economic prosperity of Belarus is another contributing factor to Lukashenka's likely re-election.
ALEXANDER LUKASHUK, RFE/RL Belarusian Service director, emphasized the government's control of the media in Belarus, saying that the Belarusian people are being deprived of both information and public discussion about election issues.