Russian police raided the home of opposition activist Lyubov Sobol early on Friday and then took her in for questioning, Kremlin critic Alexei Navalny and his supporters said.
Navalny's supporters said they thought the police action was a response to her trying to knock at the door of an alleged FSB security agent in Moscow who Navalny says took part in a botched plot to poison him in August.
The FSB has dismissed Navalny's allegations as a provocation.


US military targets IS in Syria strikes
One dead in Australian bush fires
Trump says US needs to own Greenland to deter Russia, China
Kyiv scrambles to repair ruined power grid after Russian attack
Swiss prosecutors summon owners of ski resort bar after deadly blaze