Ukrainian President Petro Poroshenko has said that Ukraine is beginning a discussion with NATO on a membership action plan.

"We consider it necessary to start discussing the membership action plan, and today we've clearly stated this, and our proposals as for the discussion have kindly been accepted," Poroshenko said at a joint press conference with NATO Secretary General Jens Stoltenberg in Kyiv on Monday.

Ukraine doesn't meet NATO accession criteria at the moment, he said.

"We have a plan for these three years, through 2020. We know clearly what to do. It's the first time Ukraine has a clear road map of what is to be done and when, and when Ukraine will meet the criteria, when reforms are implemented," he said.

Stoltenberg said NATO would continue supporting Ukraine on its path to closer relations with the Alliance and assist it in pursuing reforms and switching to NATO standards.

It is solely for the NATO members and Ukraine to decide on NATO membership when the time is right, he said.