MOSCOW—Protests in Russia over the jailing of opposition leader Alexei Navalny are threatening to escalate into a larger movement against the Kremlin, driven by frustration over falling living standards and shrinking political freedoms as President Vladimir Putin cements his long-term hold on the country.

The Russian leader for years has ridden the popularity generated by his aggressive foreign policy that has seen Moscow defy the West with hacking attacks and military interventions in Ukraine and the Middle East, and re-establish itself on the global stage since its decline under Boris Yeltsin in the 1990s.

But the weekend protests over the detention of Mr. Navalny on his return to Russia after recovering from a poisoning attack are threatening to turn into a broader movement. Discontent is now shifting to anger after a court ordered Mr. Navalny to be held in pretrial custody for 30 days, propelled by chronic corruption, the pain from the collapse of oil prices last year and Covid-19 lockdown measures.

“We have a real problem with corruption, on the one hand, and with poverty, on the other hand,” said Evgeniya Ragozina, a 28-year-old lawyer who braved temperatures of minus 20 degrees Fahrenheit to join a rally in the Siberian city of Tyumen. She added that Mr. Navalny’s arrest was just the trigger.

“People are more scared of the fact that they don’t see a decent future for themselves,” she said. “That’s why I will be [protesting] until the end of Putin’s political regime.”