Vladimir Putin will be inaugurated today for his fourth Kremlin term under the shadow of hugely strained ties with the West and a crackdown on the opposition, with Alexei Navalny and hundreds more detained at the weekend.

Opposition leader Navalny was held along with nearly 1,600 of his supporters on Saturday during nationwide rallies against Putin as police and paramilitary activists used force to break up demonstrations in Moscow and Saint Petersburg.

Putin, who has ruled Russia for 18 years and used his last term to annex Crimea from Ukraine in 2014 and launch a military campaign in Syria on the side of Bashar al-Assad the next year, has promised to improve living standards at home during his next Kremlin stint.

But he has remained silent on the issue of his succession -- despite this being an inevitable concern as the constitution bars him from running again when his fourth term ends in 2024.

Putin has struggled to revive an economy that crashed after Moscow was hit with Western sanctions over its annexation of Crimea in 2014, followed by a fall in global oil prices in 2016.

Despite this, his victory in the March election was never in question and the prospect of an inauguration in the Kremlin's gilded Andreyevsky hall has generated little excitement.

This year Putin's minders are reportedly planning a fairly low-key inauguration ceremony that will not include a lavish Kremlin reception in an apparent effort to eschew any bad publicity.

Protest leader Navalny, who was barred from challenging Putin in the March election, had called on Russians to stage a day of rallies across the country on Saturday under the catchy slogan "Not our Tsar".

Political analysts said that Moscow's attitude towards the West -- which has only hardened over the crises in Ukraine and Syria, as well as accusations of spy poisoning in the UK and election meddling in the US -- was also unlikely to change under Putin 4.0.

"For Putin any concession is a sign of weakness, so there shouldn't be any expectation of a change in foreign policy," said Konstantin Kalachev, the head of the Political Expert Group think tank in Moscow.

Kalachev suggested the president could leave the Kremlin before he serves out the six years.

"He will stay in power, but not necessarily in the presidency," he said.

“For Putin to write his place in history, he needs to pick the right moment to go. Serving another six years is a road to nowhere. He will leave in a way that takes everyone by surprise."