Ukrainian President Petro Poroshenko has said that Ukraine is to cope with two challenges on the way to the European Union (EU): to fight Russian aggression and conduct reforms.

"We are to overcome two key challenges to realize this goal. First is effective counteraction to Russian aggression. We have built the Ukrainian army in two years with the help of volunteers and each Ukrainian citizen," he said in Kyiv on Saturday during the flag-raising ceremony near the presidential administration on the occasion of Europe Day in Ukraine.

The second challenge is conducting key, systemic and comprehensive reforms.

"Reforms that would change Ukraine, reforms that would build Europe in Ukraine, restore justice and make Ukraine the extremely effective state," he said.

Poroshenko said that the road map for these reforms is the Ukraine-EU Association Agreement and the Visa Liberalisation Action Plan (VLAP) that Ukraine has implemented.

"Reforms are changes to the Constitution in part of rule of law, judicial reform. This is the step for establishing justice. Reforms are powerful anti-corruption steps," the president said.