A Russian performance artist was hospitalised on Sunday after stripping naked and nailing his testicles to a Red Square cobblestone in protest against the Kremlin's crackdown on political rights.
A video of the graphic action, available on Russian websites, showed artist Pyotr Pavlensky sitting naked outside Lenin's Mausoleum being covered with a blanket by police officers while horrified passersby looked on.
The state-run RIA Novosti news agency said Pavlensky was taken to a police station after being treated in a central Moscow clinic.
The Saint Petersburg-based artist said in a statement posted on the Grani.ru website that he was trying to draw attention to Russian society's inaction in the face of the development of a "police state".
Russia marked its annual Police Day holiday on Sunday.
It is not the first time the 29-year-old has resorted to eye-watering methods of protest.
He has previously sown his lips together to demonstrate against the jailing of two female members of the Pussy Riot punk band who staged an anti-Kremlin performance inside Moscow's main cathedral in 2011.
He was also arrested after wrapping his naked body in barbed wire outside a Saint Petersburg government building in May.