By Bond Robertson 
European aviation authorities have urged airlines to “exercise caution” when flying over the area around Ukraine, the Financial Times writes.
The reason is the increased risks involved in flying in the region.
Images from the air traffic control service Flightradar24 show that Ukraine and parts of Russia have been emptied of civilian aircraft.
Ukraine closed their airspace, while Moldova and Belarus both closed parts of their airspace, Reuters writes.
There is a particularly high risk that a civilian aircraft will be intentionally shot down, and that someone will misidentify a civilian aircraft, the European aviation authority wrote in its warning.
Reuters estimates that the situation will affect about 600 flights per day.
Throughout the day, there were a large number of reports from the Russian and Ukrainian sides that military planes, helicopters and drones were shot down.
There was heavy fighting in large parts of Ukraine until Thursday, after Russian forces attacked the country tonight.
Zelensky wrote on Twitter that on Thursday afternoon Russian forces captured an airfield outside Kiev. Earlier, Russian authorities said they had destroyed more than 70 military facilities, including 11 air strikes and a naval base.