Moscow (AFP) -
Russian police detained aides of Kremlin critic Alexei Navalny and raided his offices Wednesday ahead of nationwide protests called for the day of President Vladimir Putin's annual state of the nation.
Just hours before Putin was due to deliver his address to lawmakers and regional governors, Russian police swept in on supporters of Navalny, Putin's most outspoken opponent who is in prison on hunger strike.
Two close aides were detained by police in Moscow while monitors reported police raids on Navalny's offices in Saint Petersburg and arrests of his supporters across the country.
Navalny's team called for the demonstrations in more than 100 cities on Wednesday, after the opposition figure's doctors said his health was failing following three weeks on hunger strike.
Security forces had issued a warning against taking part in 'illegal gatherings' on Wednesday and appeared to be moving quickly to deter protesters.
Police yanked Navalny ally Lyubov Sobol out of a taxi near Navalny's main offices in Moscow on Wednesday and detained her, Sobol's lawyer said.
Spokeswoman Kira Yarmysh said she was also detained at the entrance to the building, while independent monitor OVD-Info said police had conducted searches and detained activists in at least 20 cities across the country.
Putin's annual speech sets the political agenda for the year and in 2020 saw the longtime Russian leader lay out a plan that eventually gave him the power to stay in office until 2036.
This year's address comes with Moscow locked in diplomatic disputes with the United States and Europe over Navalny, a Russian troop build-up on Ukraine's borders and a series of espionage scandals.
With parliamentary elections due in September, Putin will be looking to shore up his public support and is likely to remain defiant with the West, as well as announcing a series of measures to boost Russia's pandemic-hit economy.
But the speech threatens to be overshadowed by country-wide demonstrations called by Navalny's supporters, who fear Navalny's life is in grave danger.
Navalny's team has called for protests from 7:00 pm in cities across Russia to support the anti-corruption campaigner, who launched his hunger strike three weeks ago to protest his lack of medical treatment in prison.
- Fears for Navalny's life -
Navalny was detained when he returned to Russia in January after months recovering in Germany from a near-fatal poisoning he blames on the Kremlin -- an accusation it rejects.
He was sentenced to two-and-a-half years on old fraud charges his supporters say were politically motivated and has been serving time in a penal colony about 100 kilometres (60 miles) east of Moscow.
His team this weekend announced the protests to coincide with Putin's speech, after his doctors said Navalny was suffering from a range of ailments in prison and could die at 'any minute'.
The European Union and the United States have imposed sanctions on Russia over Navalny's poisoning, and on Monday threatened Moscow with further penalties in the event of his death.
Putin is unlikely to mention the Navalny case -- he refuses to say his chief critic's name and the Kremlin continues to dismiss him as an ordinary prisoner.
But he is almost certain to touch on other sources of contention with the West, especially over Ukraine.
A Russian troop build-up on the border with Ukraine -- where Kiev's forces have been battling pro-Russia separatists since 2014 -- has sparked widespread alarm and warnings from NATO.
Ties with the West have also been hit by a series of spy scandals.
A number of European countries have accused Moscow of increasingly aggressive espionage tactics and expelled Russian diplomats.
- Biden summit offer -
Washington last week announced sanctions and the expulsion of 10 Russian diplomats in retaliation for what the White House says is the Kremlin's US election interference, a massive cyber attack and other hostile activity. Russia has vowed to respond in kind.
As tensions peaked last week, US President Joe Biden spoke to Putin by phone, inviting him to hold a summit in a third country. The Kremlin has said it is considering the offer.
During his speech last year, Putin set out a series of constitutional reforms that were eventually approved in a referendum and reset presidential terms so he could run twice more after the end of his current six-year term.
He has said this year's address will focus on efforts to relaunch the Russian economy after the coronavirus pandemic and to turn around a decline in Russians' spending power.
Concrete economic improvements will be crucial for Putin going into September's elections.
While the president himself remains widely popular, his United Russia party is seen as stagnant and corrupt. One poll last month by the Levada Centre predicting it would win only 21 percent of the vote.