Ukrainian President Petro Poroshenko has signed a constitutional amendment committing the country to becoming a member of NATO and the European Union.
Addressing parliament on February 19, Poroshenko said he saw securing Ukraine's membership in NATO and the EU as his "strategic mission."
Ukraine should "submit a request for EU membership and receive a NATO membership action plan no later than 2023," the president told the Verkhovna Rada.
However, he acknowledged that his country needs to come a "long way" to meet the criteria of joining both institutions.
European Council President Donald Tusk attended the signing of the constitutional amendment in the parliament building.
Addressing the lawmakers in Ukrainian, Tusk, who is Polish, said that "there can be no Europe without Ukraine.”
He also warned Ukrainian politicians against using populist and nationalist tactics ahead of the March 31 presidential election, in which Poroshenko is running for a second five-year term.
"Go around temptations of radical nationalism and populism, as you have done so far," Tusk said in his speech.
The EU official also warned lawmakers against "internal conflicts," which he said only benefit "that third country," hinting at Russia.
Tusk is on a three-day visit to Ukraine, which is commemorating the fifth anniversary of the Euromaidan protests, which led to the ouster of Moscow-friendly President Viktor Yanukovych in February 2014.
Following Yanukovych's downfall, Russia seized and annexed Ukraine's Crimea region in March 2014.
Moscow is also supporting separatists in eastern Ukraine in a conflict that has killed more than 10,300 people since April 2014.