Universities and colleges in different Russian regions have urged students not to attend rallies, with some saying they may be subject to disciplinary action, including expulsion.
More than a dozen activists and Navalny allies in several Russian regions have been detained as well.
The move came amid media reports of calls for demonstrations — and videos of school students replacing portraits of President Vladimir Putin in their classrooms with that of Navalny — going viral among teenagers on social network TikTok.
Dozens of influential Russians, including actors, musicians, journalists, writers, athletes and popular bloggers, have come out with statements in support of Navalny, and some promised to attend the demonstrations