He wrote about this on his Facebook page.
"Congratulations to our close partner - Bulgaria - on starting first ever Presidency in the EU Council. I look forward to strengthening our ambitious agenda: deepening Ukraine's political association and economic integration with the EU and consolidating the EU's support for restoration of Ukraine's territorial integrity," the head of state said.
Poroshenko also added that "united we stand strong."
On January 1, Bulgaria began its six-month presidency of the Council of the European Union.