Russian opposition leader Navalny held ahead of March election

Russian opposition leader Alexei Navalny said on Thursday he had been detained by police, weeks ahead of a presidential election in which he has been barred from running.

Navalny said on Twitter that he was detained by police as he left from visiting the dentist. "They are taking me somewhere," he said.

Navalny, a 41-year-old anti-corruption campaigner who organised some of Russia's biggest protests of recent years, says he has been unfairly barred from contesting the March 18 presidential election over what he says is a trumped-up suspended prison sentence.

Incumbent Vladimir Putin is widely expected to win the contest, but Navalny has called for a nationwide boycott aimed at undermining Putin's legitimacy by bringing the turnout down.

Navalny's detention on Thursday followed shortly after his campaign chief, Leonid Volkov, also said on Twitter that he had been detained by police at Moscow's Sheremetyevo airport.

Tweeting before his detention, Navalny said Volkov had been planning to fly to the Russian regional republic of Bashkortostan to organise election-monitoring activities.