In Photos: Fortress Kyiv

A man fills sandbags in the center of Kyiv on March 7 as volunteers from the Territorial Defense Forces patrol in the background. 

A woman walks in front of a concrete blockade and anti-tank obstacles known as "Czech hedgehogs." The metal obstacles can stop light armored vehicles and remain effective even if knocked out of position by an explosion. 

Members of Ukraine's Territorial Defense Forces at a Kyiv movie theater used as a base by the volunteer fighting force on March 7. 

A member of Ukraine's Territorial Defense Forces stands guard with a hunting rifle in the suburbs of Kyiv on March 4. The Territorial Defense volunteers are a grouping of trained civilians under the command of the Ukrainian military whose tasks include armed resistance to invasion and the "protection of public authorities, local governments, critical facilities, and communications." 

Members of the Territorial Defense Forces play checkers with Molotov cocktails in Kyiv on March 6. A reported 100,000 civilian volunteers have signed up to the Defense Forces since Russia launched a full invasion of Ukraine on February 24. 

A Ukrainian serviceman at a bunker in a forest on the outskirts of Kyiv on March 6. 

A heavily armed Ukrainian soldier on March 5 in Irpin, a northwestern suburb of Kyiv. Irpin was pounded by Russian air strikes and has been cut off from electricity, water, and heating for three days.

Twists of sharpened rebar and tires lie across a road at a checkpoint in Kyiv on March 6. 

A member of Ukraine's Territorial Defence Forces is seen at a fortified checkpoint in Kyiv on March 4. 

Czech "hedgehogs" line a pavement in front of a sign saying, "I Love Ukraine," in central Kyiv on March 7. 

Men emplace sandbags in front of Kyiv's iconic Independence Monument on March 5. 

Concrete blockades in central Kyiv on March 5 spray-painted with the slogan, "Glory to Ukraine!" 

A volunteer waits for the end of curfew in the basement of a building in Kyiv on March 7. Thousands of Kyiv civilians are currently sheltering underground in basements that double as bomb shelters, and in the city's subway system, amid fears Russia will launch missiles into the center of the capital. 

A member of the Territorial Defence Forces stands guard at a checkpoint in Kyiv on March 3.