Turkish President Recep Tayyip Erdogan and his Ukrainian counterpart Volodymyr Zelensky on Friday held a phone conversation to discuss the situation in Ukraine.

The two leaders discussed the situation on the ground and the stage of negotiations between Russia and Ukraine, according to a statement issued by the Turkish presidency.

Erdogan told Zelensky that he once again had emphasized Turkey's support for Ukraine's territorial integrity at the NATO leaders' summit, which was held in Brussels Thursday, said the statement.

The Turkish president said he had told the leaders of NATO members about Turkey's "active and principled policy, and the effective diplomatic efforts comprehensively."

"Turkey has put into practice all the help it can in this process," Erdogan told Zelensky.

Earlier in the day, Erdogan said he would make a phone conversation with the Ukrainian president, and with Russian President Vladimir Putin this weekend or early next week, to inform them about his discussions at the extraordinary NATO summit.

"I may probably talk with Putin either this weekend or early next week," the semi-official Anadolu Agency quoted Erdogan as saying.

"As we will evaluate the meetings at the NATO (summit), I will tell him 'Now you should be the architect of a step to be taken for peace' for the next process. We should find a way to end this by suggesting him 'Make an honorable exit'," Erdogan said.

Moscow and Kiev were close to an agreement on four issues including Ukraine's neutrality, partial disarmament, security guarantees, and the use of the Russian language in Ukraine, the Turkish president told journalists on his flight from Belgium to Turkey.

But the Russian demands on the future status of Crimea and Donbass continue to be the most important disagreement in negotiations, he said.

Last week, Erdogan renewed his offer to bring the leaders of Russia and Ukraine together in Turkey for final decisions on these topics.