Police in Kyiv have said they are inspecting schools for bombs as students return for a new academic year. Meanwhile, Russian President Vladimir Putin is set to host his Turkish counterpart next week.
Police forces were checking educational facilities in Kyiv on Friday, following reported bomb threats in the capital's schools.
Some 4 million students are returning to schools, both physically and through virtual classes, Ukraine's Education Ministry said.
Meanwhile, the Kremlin announced on Friday that Turkish President Recep Tayyip Erdogan is traveling to Russia's Black Sea resort of Sochi on Monday for talks with President Vladimir Putin.