A day after Russian President Vladimir Putin ordered military action in the breakaway regions of Ukraine, Russian forces appear to be closing in on the Ukrainian capital of Kyiv.
Russian troops have entered the Obolon district of Kyiv, Ukraine's defense ministry reported.
Russian troops are attempting to infiltrate the capital, Ukrainian authorities warned.
The official Twitter account for the cabinet ministers of Ukraine warned that Russian troops are cunningly trying to break into Kyiv. They seized two Ukrainian military vehicles, changed into Ukrainian military uniforms, and drove to the center of Kyiv.
The Ukrainian military flagged that vehicles have been seized by Russian troops, warning that Russia is using them to penetrate Kyiv. It highlighted vehicle tags, urging Kyiv residents to call the police.
Russian troops appear to have reached the town of Vorzel, on the outskirts of Kyiv, on Friday morning, the Ukrainian Ministry of Defense announced.
Explosions could be heard in Kyiv early Friday local time. Many Ukrainians had rushed to leave the capital Thursday.
"Russian mechanized forces, which came in from Belarus, are 20 miles outside of Kyiv," Defense Secretary Lloyd Austin told lawmakers Thursday night, according to reporting from Axios. Austin added that the military is looking into ways to provide Ukrainian forces with more equipment, including ammunition.
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Kyiv residents reported loud explosions, the Kyiv Independent reported. Ukrainian forces might have shot down a Russian missile in the capital, according to the Ukrainska Pravda news outlet.
Ukraine's foreign minister, Dmytro Kuleba, noted that the last time foreigners attacked Kyiv took place in 1941.
"Horrific Russian rocket strikes on Kyiv. Last time our capital experienced anything like this was in 1941 when it was attacked by Nazi Germany," Kuleba said. "Ukraine defeated that evil and will defeat this one. Stop Putin. Isolate Russia. Severe all ties. Kick Russia out of [everywhere]."
Russian shelling outside Kyiv had already done significant damage.
The Ukrainian Ministry of Defense claimed that Russia had lost an estimated seven aircraft, six helicopters, more than 30 tanks and 800 troops, as of 3 a.m. Friday. It was not clear what Russia's take is on the number of casualties it has incurred.
Kyiv Mayor Vitali Klitschko reported that three people were injured, one in critical condition, as a result of a rocket explosion in a residential building.
The Kyiv Independent posted photos of the destruction.
Russian forces were attacking through three corridors, the official said in a report the Department of Defense released Thursday.
There was also fighting around Kharkiv, the country's second-largest city located near the border with Russia in the east.
Russian forces also attacked from the Black Sea peninsula of Crimea in southern Ukraine, which Russia illegally seized in 2014. The Pentagon report stated that those three "axes" were designed to take key population centers.
This is a developing story. Check back for updates. Fox News' David Aaro contributed to this report.