US Secretary of State Condoleezza Rice has met Belarusian dissidents on the sidelines of a Nato summit in neighbouring Lithuania.
Rice has called for a credible alternative to Lukashenko
She told them there will be "a road to democracy in Belarus", which she has described as the "last true dictatorship" in central Europe.
She defended the right to public protests and called for a free media as well as credible elections.
Belarus and Russia have accused Ms Rice of meddling in the country's affairs.
Ms Rice met the seven Belarusian dissidents in the Lithuanian capital, Vilnius, where she is attending Nato meetings with foreign ministers.
Nikolai Cherginets, a senior MP in the Belarusian parliament, condemned the meeting as a "return to the times of the Cold War".
"It's a call for an overthrow of the legally elected authorities in Belarus," he said.
"While it may be difficult and long and at times even far away, there will be a road to democracy in Belarus," Ms Rice said.
But she refused to be drawn on plans by dissidents to hold mass street protests, such as those witnessed in Ukraine and Georgia which led to regime change.
"The people of Belarus will have to make determinations about how they move forward," she told a news conference on Thursday.
"But the key here is that people ought to be able to protest, to speak their minds, there ought to be free media," she added.
She said the presidential election scheduled for 2006 would offer "an excellent opportunity" for the people of Belarus to voice their will.
"We will support the idea that elections, when they are held, should be free and fair," she added.
The seven dissidents announced plans for massive street protests against the authorities in the Belarusian capital, Minsk.
Alexander Dobrovoskiy, deputy chairman of the United Civic Party, who was at the meeting, said Ms Rice supported the creation of a credible political alternative to the current regime.
But the opposition is divided and, despite more than a decade of rule by Alexander Lukashenko, has failed to find a figure-head to unite around, says the BBC's regional affairs analyst Steven Eke.
He says the Belarusian government is now likely to use Ms Rice's comments as evidence of western interference, and to bolster its own, fiery, anti-Western propaganda.
For Russia, our correspondent says Belarus is an important defence partner and a vital part of its gas export pipeline network.
For these reasons, he says the Russian foreign ministry has already said it rejects the need for "regime change".