Russian-installed authorities in Kherson ordered residents to immediately leave the area as Ukrainian forces close in on the eastern Ukrainian city, which they captured in the early days of the war.
Russian authorities urged people to cross the Dnieper River into Russian-controlled territory.
Due to the tense situation at the front, authorities pleaded with residents to take care of their families and friends.
Russia has been bombarding residential areas near the frontline in recent weeks, which western leaders have condemned as war crimes.
Russian strikes have also targeted critical infrastructure, power plants and heating facilities, causing widespread power outages in several regions in an apparent bid to reduceUkraine's energy supplies as it heads into the winter
As Ukrainian forces have made major territorial gains into Russian-controlled territory, Russian President Vladimir Putin ordered a "partial mobilize" of 300,000 reserve troops to fight in the war.
Russian officials began moving civilians out of the region earlier this week, despite warnings that a Ukrainian attack could be imminent.
Russian forces have suffered a number of setbacks since September. Last month, the Ukrainian military broke through the Russian frontline into the Kherson region, making their biggest counteroffensive since the Kremlin invaded. Although Ukraine did not take credit for the explosion that destroyed parts of the bridge, it is believed that it was caused by Putin. It is important for the region to have access to Kherson, the Dnieper River and the Black Sea ports.
Russian officials said their forces prevented a Ukrainian offensive into Kherson. All attacks were repelled and the enemy was pushed back to their initial positions, according to the country's Defense Ministry.
In eastern and southern Ukraine, Putin declared martial law this week. The order was also applied to the east of the country. Putin said in a televised statement the move would enhance economic stability in the area, but western officials warned it could prevent citizens from leaving. The Kremlin has no plans to close its borders.
The Russian authorities ordered the evacuate of Kherson.
Putin has declared martial law in Russian-occupied Ukrainian Territories.