Russian opposition leader Aleksei Navalny is calling on "all patriots" in the country to join nationwide anticorruption rallies on June 12.
Navalny issued the call on his website on April 12, two days after he was released at the end of a 15-day jail term that followed his arrest at a protest in Moscow.
A vocal Kremlin opponent, Navalny is seeking to build up grassroots opposition to President Vladimir Putin's government ahead of a March 2018 presidential election in which he is seeking to run.
Tens of thousands of Russians turned out on March 26 for protests that he orchestrated to highlight alleged corruption among senior Putin allies, including Prime Minister Dmitry Medvedev.
June 12 is Russia Day, a holiday marking Russia's proclamation of sovereignty within the Soviet Union in 1990.
"What I am seeing is that patriots took to the streets on [March] 26 and they were confronted by traitors and thieves," Navalny said in a video message. "What should patriots like us do? They ought to celebrate Russia Day."
"On June 12, on Russia Day, I call on all patriots in the country, regardless of their political views, to join anticorruption rallies with Russian flags and with a renewed demand for answers to our reasonable questions," he added.
The March 26 protests were the biggest antigovernment demonstrations in Russia since a series of rallies that Navalny helped lead in 2011-12.
Police detained more than 1,000 people in Moscow alone.
Navalny urged people to take to the streets across Russia on June 12 to "show clearly and uncompromisingly that -- no, guys, we are not withdrawing our claims about corruption."
"We will never do it, because corruption in Russia is the cause of poverty, the cause of low wages, the cause of the terrible state of all branches of the economy," he continued.
Former oil tycoon Mikhail Khodorkosky, a Putin foe who spent 10 years in prison and now lives in Europe, has called for protests on April 29.
Navalny did not mention that in his video message.