More than 1,000 supporters of jailed opposition leader Alexei Navalny rallied in rainy Moscow on President Vladimir Putin's 65th birthday, calling for the Russian strongman to retire.

The rally on Pushkin Square -- along with protests in dozens of other cities -- was called by Navalny, a 41-year-old anti-corruption campaigner, who has declared his intention to run in a presidential election next March to unseat Putin.

More than 1,000 people turned out despite the bad weather, AFP reporters said, while police put the number at 700 people including journalists.

Smaller rallies and pickets took place in other cities across Russia.

Eighty people were detained in 21 cities including the exclave of Kaliningrad, the Black Sea resort of Sochi and Yuzhno-Sakhalinsk in the Far East, said OVD-Info, a group that monitors politically-motivated arrests.

In Moscow, the crowd of mostly young protesters chanted "Happy birthday" and "Russia without Putin" and many held copies of the constitution and flags amid honks of support from passing cars.

The demonstrators gathered in the centre of the city, defying a ban on rallies in the heart of Moscow. 

Hundreds of policemen, some in riot gear and with dogs, were out on the streets to prevent people from going to Red Square.

Navalny was arrested late last month as he was planning to travel to a rally in a provincial city, part of his long-shot bid for the presidency.

 A court on Monday sentenced him to 20 days in jail on charges of repeatedly violating a law on organising public meetings.

- 'Better than Putin' - 

Svetlana Kiseleva, a 20-year-old student, said she did not support Navalny but joined the Moscow rally to demand political competition.

"It's important to have a choice, to have an opposition," she told AFP. "I still think he would be better than Putin anyway. I'm not happy with Putin."

Orest Cherchesov, a 43-year-old manager, also said he was not a Navalny fan but wanted to see competitive elections.

"There are people who think differently in Russia, just like there were in Nazi Germany," he said. "I believe he has the right to run in the elections."

Putin, who has ruled since 1999, turned 65 -- the retirement age for Russian officials -- and many protesters urged him to retire.

He said this week he has not yet decided whether to seek another six-year term. But he is widely expected to run in -- and win -- the March election.

Navalny's campaign team had released a series of video addresses of prominent figures calling on Russians to take to the streets.

- 'Revolting spectacle' -

In an unusually strong address, one of Russia's most acclaimed film directors, Andrei Zvyagintsev, slammed Putin for hindering Navalny. 

He criticised the prospect of Russians voting in polls where "we are asked to choose one out of one".

"It's just revolting watching this spectacle," he said.

Entrepreneur Evgeny Chichvarkin, who lives in self-imposed exile in Britain, added: "Gulag is awaiting us without political competition."

Navalny, the Yale-educated lawyer with a street-smart image and a penchant for catchy slogans, compared life under Putin's regime to a forced diet of "turnip."

"If we do nothing, they will be feeding us this damn turnip for the rest of our lives. And our children too," he said in an address dictated from his cell earlier this week.

Navalny brought tens of thousands of supporters -- many of them students and schoolchildren -- onto the streets for unauthorised protests across the country in March and June.

The protests ended in violent clashes, and police arrested more than 1,000 people in Moscow alone at the March demonstration.

Navalny himself was detained even before arriving at those two rallies and served 15 and 25 days in jail for organising the events. Several protesters were given lengthy prison terms.

And in the past few days, Navalny's Moscow campaign headquarters and several other offices have been raided.

Officials say he is not eligible to run for president because he is serving a suspended sentence for fraud.

The Kremlin said Putin had received "numerous congratulatory messages and telegrams" including from 11 heads of state.

Source: AFP