Kyiv will once again consider decentralization amendments to Ukraine's constitution after appropriate conditions are created in the sphere of security in Donbas, Ukrainian President Petro Poroshenko has said.

"It is obvious that in order to introduce changes to this part of the constitution, there are clear preliminary conditions, primarily in the sphere of security. A complete and lasting ceasefire regime should be established," he said at a Verkhovna Rada session on the occasion of the 20th anniversary of the adoption of Ukraine's constitution.

"The OSCE SMM [Organization for Security and Cooperation in Europe Special Monitoring Mission] should receive full access to the entire territory not controlled by Ukraine, as well as establish constant monitoring at the temporarily uncontrolled sector of the Ukrainian-Russian border," he said.

All illegal armed units should disarm and security zones should be established in Donbas, Poroshenko said.

"The placement of an OSCE armed police mission ought to become an important guarantee against military provocations, to observe the ceasefire, as well as ensure the security of the future electoral process," Poroshenko said, adding that he was also speaking about the release of all Ukrainian 'hostages'.

The local elections in Donbas should be held in compliance with Ukrainian legislation and OSCE standards, the president said.

"Only if these conditions are met will I be ready to call on the Verkhovna Rada to vote for these changes at second reading," he said.

However, "this will not happen today, tomorrow or on July 4, as some have said, but when these clear preliminary security conditions are fulfilled," he said.