The Russian Prosecutor General's office has launched a probe against a consumer rights group that has cautioned Russians against traveling to Crimea.

Acting on a request from prosecutors, the government communications watchdog on Monday quickly blocked the website of the Society for Protection of Consumer Rights.

Last week, the group published a notice warning Russians that after visiting the Black Sea peninsula without permission from Ukrainian authorities they could face criminal punishment in Ukraine. The group argued that Russia's annexation of Crimea violated both international law and treaties Russia signed with Ukraine.

Russia annexed Crimea in March 2014 weeks after the ouster of Ukraine's former Moscow-friendly president. The U.S., the European Union and other countries have responded by imposing economic sanctions on Russia.