* Kremlin critic Navalny's treatment sparked protests
* Allies have urged supporters to gather outside homes
* Russia could face new Western sanctions
By Gabrielle Tétrault-Farber
MOSCOW, Feb 14 (Reuters) - Supporters of Kremlin criticAlexei Navalny plan to hold candle-lit gatherings in residentialcourtyards across Russia on Sunday despite warnings that theycould be arrested.
Navalny's allies have declared a moratorium on streetrallies until the spring after police detained thousands ofpeople at protests in the past few weeks against the oppositionpolitician's arrest and imprisonment.
But they want Russians to show solidarity with Navalny bygathering outside their homes for 15 minutes on Valentine's Dayevening, shining their mobile phone torches and arrangingcandles in the shape of a heart.
"(President Vladimir) Putin is fear. Navalny is love. That'swhy we will win," Leonid Volkov, one of Navalny's close allies,wrote on Twitter when calling on people to gather.
Navalny was arrested last month on his return from Germanyfollowing treatment for poisoning, in Siberia, with what manyWestern countries say was a nerve agent. He was jailed on Feb. 2for violating parole on what he said were trumped-up charges.
He blames Putin for the poisoning, and Western countries areconsidering new sanctions against Russia. The Kremlin denies anyinvolvement and questions whether Navalny was poisoned.
Volkov, who is based in Lithuania, is one of several Navalnyallies now abroad or under house arrest in Russia.
He urged people to flood social media with pictures ofSunday's gatherings - a new venture for the opposition thatresembles political actions in neighbouring Belarus - using thehashtag #loveisstrongerthanfear in Russian.
Another activist has called on women to form a human chainon a pedestrian street in Moscow on Sunday afternoon in supportof Navalny's wife Yulia, who according to media reports flew toGermany this week, and other women affected by the policecrackdown against protesters.
Russian law enforcement agencies said on Thursday thatpeople taking part in unsanctioned rallies could face criminalcharges.
Some rights groups accuse police of using disproportionateforce against protesters in recent weeks. The Kremlin has deniedrepression by police and says the protests were illegal as theywere not approved and risk spreading COVID-19.(Reporting by Gabrielle Tétrault-FarberEditing by Timothy Heritage)