Russian opposition leader Alexei Navalny has been given a 20-day prison sentence for repeatedly violating a ban on organizing public meetings.
His supporters say he was detained to stop him taking part in presidential elections in March when Vladimir Putin is expected to seek a fourth term.
It is the third time this year that Mr. Navalny has been jailed.
Russia’s electoral authorities say he cannot stand in the March vote because of a separate suspended sentence.
That conviction for embezzlement was condemned last month by the Council of Europe’s committee of ministers as “arbitrary and unfair”.
His latest sentence came after he tried to organize a rally on Friday in Nizhny Novgorod, about 400km (250 miles) east of Moscow. The authorities said he did not have permission to organize such events.