At the beginning of Sunday, a large explosion illuminated the night sky near Kiev, the capital of Ukraine, as Ukrainian troops continued to oppose Russia's attempt to seize control of the city. 

The explosion occurs when Ukrainian troops are fighting fierce battles with Russian troops in several cities across the country. Meanwhile, ordinary Ukrainians and military reserves unite to protect their homes and families from the Russian invasion. 

Russia faces unexpected difficulties in supplying its troops, suffering unexpected losses in personnel, armor and aircraft. Russia has not yet established air sovereignty over Ukraine, U.S. officials said, Ukraine's air force and their air defense system are fighting for airspace control. Without indisputable control of the sky, it would be more difficult for moving troops to see and attack targets from the air. 

So far, these challenges have prevented the rapid overthrow of major Ukrainian cities, including the capital Kiev, and US officials say it could occur within a few days. The city of Kharkiv, near the Ukrainian-Russian border, has not fallen into invading forces either, but authorities are afraid that it could happen on the first night of the invasion. According to a local hospital, 

Ukraine  reported the deaths of several civilians, including a 6-year-old boy who died in a violent gunshot in the western part of Kiev on Saturday night. According to the Ukrainian National Emergency Medical Service, a  woman was killed after a nine-story apartment in the eastern city of Kharkov was attacked by an "enemy cannon" on Saturday night. 

As the fighting intensifies, the rebellious Ukrainian President Volodymyr Zelensky appears on the streets in a series of self-made videos urging citizens to protect their country. In Kiev alone, authorities have armed reserves with 18,000 firearms and ammunition, and Ukrainian television broadcasts instructions on how to make Molotov cocktails. Ukrainian men between the ages of 18 and 60 cannot leave the country.  At the same time, thousands of Ukrainians are fleeing for their lives. The Polish border guard said on Saturday that 100,000 people have entered Poland from Ukraine since the invasion began on Thursday.