A top ally of Russian opposition leader Alexei Navalny has urged residents of big cities to gather in residential courtyards on Sunday evening with their mobile phone torches on.
Leonid Volkov said the protest will start at 8pm local time and last for 15 minutes.
Mr Volkov wrote in a Facebook post that the new rally format -similar to the tactics opposition supporters employed during protests in neighbouring Belarus - could prevent Russian police from interfering and allow anyone to participate.
The protest will coincide with Valentine's Day.
"You will raise your phone flashlights - and someone, maybe, will bring candles - and form a heart shape with them... You will take a picture of it from above, from one of the apartments, and post it on Instagram. Let's have social media feeds filled with thousands of shining hearts from dozens of Russian cities," Mr Volkov wrote. Mr Navalny (44), was arrested on January 17 upon returning from Germany, where he spent five months recovering from a nerve-agent poisoning that he blames on the Kremlin.