Ukraine's Prime Minister Volodymyr Hroisman wrote on his Facebook page, Censor.NET reports citing BBC.
"Today is not the best day for united Europe," he wrote.
"However I believe that the unity of European nations will be maintained after all. Because it is based above all on democratic values which are common for all.
"We, Ukrainians, remain committed to these European democratic values. We have suffered a lot for our European choice and continue to pay a high price while protecting not only our sovereignty but also the eastern border of Europe. Therefore we will continue to fight for a strong and united Europe and invigorate European integration processes," Hroisman wrote.
As reported, supporters of UK leaving the EU cast more votes in the Brexit referendum than those who prefer the country to remain in the Union. According to the latest data, 51.9 percent of referendum participants said Leave.