Russian police have arrested opposition leader Alexei Navalny in the capital, Moscow, after he joined nationwide protests he organised demanding fair presidential elections.

A video posted on his Twitter account on Sunday showed several policemen wrestling him to the ground before dragging him into a police bus, surrounded by a crowd of supporters and journalists.

"I have been detained," Navalny tweeted. "This means nothing. Come to Tverskaya [Avenue]. You are not coming for me, but for yourself and your future," he said, referring to Moscow's main thoroughfare.

Earlier on Sunday, Russian police raided Navalny's Moscow office during a live online broadcast of the nationwide protests demanding fair presidential elections.

Roman Rubanov, director of Navalny's Anti-Corruption Foundation, wrote on Twitter on Sunday morning that the police accused one of the show presenters, Dimitry Nizovtsev, of having a bomb in his phone.

According to the live broadcast from the office, Nizovtsev was arrested.

Ведущего Новостей Дмитрия обвиняют в заложении бомбы. pic.twitter.com/Hg8g3FEcIV — Рубанов Роман (@rrubanov) January 28, 2018

The incident came after hundreds of Navalny supporters began a nationwide day of protests against authorities on Sunday, calling on voters to boycott what they said was a rigged presidential election on March 18.

According to Navalny's regional manager in Ural, Siberia and Far Eastern regions, Oleg Snov, police came to the office in Barnaul city with a search warrant, seizing 86 leaflets along with some office equipment, but the rally went through as planned.

Ksenia Pakhomova, Navalny's manager in Kemerovo region, wrote on Twitter that she was arrested an hour before the protest rally.

The protests were banned in Moscow and St Petersburg, but Navalny still brought his supporters to the streets in both cities.

Nikolai Lyaskin, Navalny's Moscow coordinator, was also arrested on Sunday, the Interfax news agency quoted him as saying.

March elections

President Vladimir Putin, in power as president or prime minister since 1999, is almost certain to win another six-year term as president on March 18.

Navalny's supporters hope the election will be undermined by a low voter turnout.

Russian electoral authorities rejected Navalny's candidacy because he was previously convicted of financial crimes, for which he received a suspended sentence.

Navalny has denied wrongdoing and condemned the charges as trumped up to thwart his political ambitions.

He has also been arrested numerous times for violating rules against holding unsanctioned public gatherings.