That number, UNHCR says, marks a 50 percent increase in just four weeks.
"If this crisis is not quickly stopped, it will have not only devastating humanitarian consequences but it also has the potential to destabilize the whole region," U.N. High Commissioner for Refugees Antonio Guterres said in response to the surge.
An estimated 94 percent of those displaced by the conflict are staying in the Donetsk, Kharkiv and Kiev regions. "Because of the insecurity, humanitarian actors have not been able to assess the situation of people displaced in the Luhansk region," noted UNHCR's Europe Bureau director, Vincent Cochetel.
Ukrainian forces are in the midst of an Anti-Terrorist Operation to regain control of the country's embattled eastern region from Russian forces and rebels. In areas where there is shelling, the U.N. cites shortages of food, water, and basic necessities. Delivery of humanitarian aid has been hampered by impassable roads.
UNHCR has so far provided Ukrainians in Donetsk and Kharkiv with over 150 tons of humanitarian assistance and hosted more than 100,000 displaced people.
Since January, 121,000 Ukrainians have applied for refugee status or temporary asylum in Russia. Half of those requests were submitted in August, the Federal Migration Service reported. Between January and July, 4,106 Ukrainians sought refugee status in the European Union.