MOSCOW — A Russian activist was detained by police Thursday after posing half-naked on a large wooden cross near Moscow's headquarters of the top national security agency, mimicking Christ's crucifixion.

Pavel Krisevich was detained after fellow activists attached him to the cross and doused the pavement in front with a liquid harmlessly burning at a low temperature. They also threw papers symbolizing criminal case materials into the flames until the police intervened.

The action organizers said they wanted to draw public attention to the activities of the Federal Security Service (FSB), the main KGB successor agency. Opposition activists have criticized the FSB for pushing politically-tinged investigations as part of the Kremlin's efforts to stifle dissent.