Belarusian courts sentenced on Thursday 30 protesters detained the previous night at rallies against President Alexander Lukashenko held across the country, human rights activists said.

Police rounded up scores of people protesting against Lukashenko and an economic slump in the former Soviet republic in a number of cities on Wednesday.

Such rallies have become regular in the last few weeks. People attending the protests, which are announced and coordinated through social networking websites, do not make vocal calls against Lukashenko or carry banners, but simply applaud in unison.

On Thursday, courts sentenced 13 protesters to between 6 and 15 days' detention, and fined 17 between $20 and $175.

Signs of unrest have been growing in the tightly-policed state with the onset of the economic crisis that has led to a 36 percent devaluation of the ruble last month and inflation that is likely to be the world's highest this year.

The opposition is in disarray after a police crackdown and mass arrests following a protest rally on December 19 against Lukashenko's re-election for a fourth straight term.

Several opposition figures who ran against Lukashenko in last year's election, which Western monitoring bodies also denounced as suspect, have since been jailed. (Reporting by Andrei Makhovsky; Writing by Olzhas Auyezov; editing by David Stamp)