- Opposition says Lukashenko rigged election.
- He denies electoral fraud, has cracked down on protests.
- His opponents call for a new wave of protests.
KYIV: Belarusian opposition figures marked an unofficial "Freedom Day" on Thursday by calling for new protests against veteran President Alexander Lukashenko to increase pressure on him to resign.
Lukashenko, 66, has faced the biggest challenge to his nearly 27-year-rule since protesters took to the streets after he was declared the winner of a presidential election last August which they said was rigged.
He denied electoral fraud and police cracked down on the protests, which attracted hundreds of thousands of people before giving way to smaller marches.
Marking the anniversary of Belarus' 1918 declaration of what was short-lived independence from Russia, exiled opposition figure Sviatlana Tsikhanouskaya wrote on Twitter: "I call on all friends of Belarus to stand in solidarity with Belarusians on Freedom Day, March 25th."
"Take political action. Hold/participate in a solidarity rally in your city. Write letters to political prisoners. Post on social media," she wrote.
Local organisers want neighbourhood marches, flash mobs and protest symbols displayed on Thursday evening, but are preparing a larger protest at the weekend.
Media and social networks showed dozens of red and white flags - a protest symbol - being displayed in cities across Belarus on Thursday morning.
Fireworks were set off in the capital Minsk on Wednesday at 23.34 local time (2034 GMT) - a reference to an article in the legal code relating to participation in protests.
The government has said it will retaliate against protests.
"These are the absolute enemies of our state ...and we will deal with them very quickly," said Nikolai Karpenkov, Deputy Minister of Internal Affairs.
The democratic aspirations of the opposition, whose leading figures are mostly in prison or exile and demand free elections, have been supported by Western countries.
Lukashenko has kept power with the financial and diplomatic backing of Russia which, according to western diplomats, sees Belarus as a buffer zone against NATO. Belarus borders Russia, Ukraine and NATO member states Latvia, Lithuania and Poland.
A diplomatic row between Belarus and Poland looks set to worsen after Andrzej Poczobut, a journalist, activist and member of an association representing the Polish diaspora, was detained in Belarus on Thursday.
An aide to Poland's prime minister said Poczobut was allegedly facing allegations of "inciting feuds between nationalities" and denounced the move as intimidation against the Polish diaspora.
His detention follows the arrest of several other Poles in Belarus including the head of the diaspora association.