Police officers detain a protester in central Manezhnaya Square in Moscow during an unsanctioned rally against the Russia’s military actions in Crimea.
Rising tensions in Ukraine sparked protests around the world this past weekend.
Dozens of protesters demonstrating against Russia's buildup of troops and military equipment in Crimea were arrested by police in Moscow and St. Petersburg on Sunday.
Russia's Interfax news agency said they were detained for "attempts to violate public order."
Hundreds of British-based Ukrainians gathered outside the Russian Embassy in London with banners demanding "Hands off Ukraine," while singing "Putin is a murderer" and "stop the occupation."
Similar protests were reported in New York, Washington, the Lithuanian capital of Vilnius, Turkey's Ankara and Georgia's capital Tbilisi.
Here are some of the more striking photos from the demonstrations: