The White House on Friday warned Americans to leave Ukraine as Russia could attack at any time with an air assault.
"Do not travel to Ukraine due to the increased threats of Russian military action and Covid-19; those in Ukraine should depart now via commercial or private means," read an updated advisory posted on the State Department's website.
The US has been releasing intelligence which it claims is proof that Russia is prepared to mount a military aggression against Ukraine any time now, but Moscow has accused Washington of "hysteria" over tensions near KIev.
Russia has concentrated more than 100,000 troops near Ukraine's border. But, said that they have no invasion plans.
South Korea has decided to ban its nationals from travelling to all regions of Ukraine and urged those staying there to evacuate immediately amid the looming tensions in the region.
The ban came amid growing tensions that Russia could launch a full-scale invasion into Ukraine, as it has deployed troops along the borders between the two countries.
"South Koreans currently staying there should evacuate immediately to safe third countries or South Korea via available flights," the Ministry said in a statement, adding those planning to travel to Ukraine must also cancel their visits.