Progress made at the peace talks between Ukrainian and Russian delegations in Turkey may pave the way for a meeting at the leaders' level, President Recep Tayyip Erdoğan said Tuesday.

Addressing the Russian and Ukrainian delegations who are in Istanbul for peace talks, Erdoğan sounded optimistic that progress can be made and said Turkey would be pleased to host a meeting between Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskyy, both of whom he referred to as "valuable friends."

"We hope the meetings will be beneficial for both countries and the region, as Turkey is deeply worried about the conflict," he said.

The president said the negotiation process between Russia and Ukraine has increased hopes for peace and that ensuring a cease-fire as soon as possible would benefit all parties. He congratulated the delegations from both sides for exerting great efforts and said that they have the prerogative to end the tragedy, which has killed thousands of Ukrainians and destroyed cities.

Stressing that Turkey has been displaying a fair stance that emphasizes the rights of both sides, Erdoğan said it is about time that the talks start producing results. He also noted that Turkey has not hesitated to undertake responsibility for peace and stability in the region.

"We believe that there will be no loser in a fair peace deal," the president said, adding that the world is awaiting good news from Istanbul.

Erdoğan said he will be leaving for the Uzbek capital Tashkent but Foreign Minister Mevlüt Çavuşoğlu will stay in Turkey for the remainder of the meetings and is prepared to provide assistance if needed.

"I know that you will not hesitate to take the initiative to re-facilitate peace," he said.

The Russian and Ukrainian delegations arrived in Istanbul on Monday.

They met at the Dolmabahçe working office in Istanbul’s Beşiktaş district.

"I can express that the phone calls we've maintained with (Russian President) Mr. (Vladimir) Putin and (Ukrainian President) Mr. (Volodymyr) Zelenskyy are heading in a favorable direction," Erdoğan said at a news conference after a cabinet meeting at the presidential complex in the capital Ankara a day earlier.

"Today, we are the country that makes the most effort towards peace, and the only country in which both sides trust its fairness, sincerity, and friendship," he said.

Security guarantees and organizing a cease-fire to resolve humanitarian problems were being discussed at talks in Turkey between Ukraine and Russia on Tuesday, an adviser to Zelenskyy said.

"Intensive consultations are underway right now on some important issues, the most important of which is agreement on international security guarantees for Ukraine, because with this agreement we will be able to end the war as Ukraine needs," said political adviser Mykhailo Podolyak said on national television.

"The second issue is a cease-fire to solve all the humanitarian problems that have accumulated," he said.

He said another problem was the "escalation of the war" including what he said, without giving details, was the "violation of the rules of war."

On Monday, Ukrainian Foreign Minister Dmytro Kuleba said his country’s most ambitious goal at talks with Russia in Turkey this week is to agree on a cease-fire.

"The minimum program will be humanitarian questions, and the maximum program is reaching an agreement on a cease-fire," he said on national television when asked about the scope of the latest round of peace negotiations. He noted that security guarantees would have to be followed by a referendum in Ukraine. Kuleba noted that the issue of holding a referendum will not be discussed in the negotiations in Turkey and that this is an internal matter of Ukraine.

After holding a phone call with Çavuşoğlu, Kuleba said he is grateful for Turkey hosting the next round of talks.

"I hope that under Turkish mediation leadership these negotiations will bring results serving the interests of peace in Ukraine and our security," he said on Twitter.

Russian Foreign Minister Sergey Lavrov also said they hope to have successful results in the peace talks.

"So far we cannot state any significant achievements or breakthroughs," Kremlin spokesperson Dmitry Peskov told reporters, adding that it was "important" that it had been decided to continue the talks in person.

Lavrov also said that a meeting between President Vladimir Putin and his Ukrainian counterpart Volodymyr Zelenskyy should happen once the two sides are closer to agreeing on key issues.

Earlier peace talks between the sides held both via video and in-person failed to make progress.

Zelenskyy hinted that Ukraine is prepared to declare its neutrality and consider a compromise on contested areas in the country’s east to secure peace – but he said only a face-to-face meeting with Putin can end the war. A meeting like that hasn't happened yet. He said late that he will insist on assurances that his country's sovereignty and territorial integrity will be respected at the meeting.

"Our priorities in the negotiations are known: sovereignty, territorial integrity of Ukraine are beyond doubt," Zelenskyy said in his nightly video address. "Effective guarantees of security are a must. Obviously, our goal is peace and return to normal life in our country as soon as possible."

"We must come to an agreement with the president of the Russian Federation, and in order to reach an agreement, he needs to get out of there on his own feet ... and come to meet me," Zelenskyy said in an interview that Russia barred its media from publishing.

Russian Foreign Minister Sergey Lavrov said Monday that the two presidents could meet, but only after the key elements of a potential deal are negotiated.

"The meeting is necessary once we have clarity regarding solutions on all key issues," Lavrov said in an interview with Serbian media. He accused Ukraine of only wanting to "imitate talks," and said Russia needs concrete results.

In an overnight video address to his nation, Zelenskyy said Ukraine is seeking peace "without delay" in the talks.

While saying "Ukraine’s sovereignty and territorial integrity are beyond doubt," Zelenskyy also suggested compromise might be possible over Donbas, the predominantly Russian-speaking eastern region of Ukraine where Moscow-backed rebels have been fighting a separatist war for the past eight years. With its forces bogged down elsewhere, Moscow recently said its focus is now on securing the Donbas.

Ankara hosted the foreign ministers of Russia and Ukraine in Antalya earlier this month. Foreign Ministers Lavrov of Russia and Kuleba of Ukraine met for talks in the Turkish resort town of Antalya, which Çavuşoğlu also attended. The talks were largely inconclusive, but Ankara considers the fact that they took place at all a success.

Maintaining its neutral and balanced stance, Turkey continues its diplomatic efforts to de-escalate the Ukraine conflict, urging all sides to exercise restraint. While Ankara has opposed international sanctions designed to isolate Moscow, it also closed its straits to prevent some Russian vessels from crossing through them.

NATO ally Turkey borders Ukraine and Russia in the Black Sea and has good ties with both. Since the beginning of the conflict, Ankara has offered to mediate between the two sides and host peace talks, underlining its support for Ukraine’s territorial integrity and sovereignty. Having recently called Russia’s invasion an unacceptable violation of international law, Turkey has carefully formulated its rhetoric not to offend Moscow, with which it has close energy, defense and tourism ties.

While forging close ties with Russia in a number of areas and relying heavily on Russian tourists, Turkey has sold drones to Ukraine, which angered Moscow. Turkey also opposes Russian policies in Syria and Libya, as well as Moscow's annexation of Crimea. President Erdoğan has repeatedly said Turkey will not abandon its relations with Russia or Ukraine, underlining that Ankara's ability to speak to both sides is an asset.

The Russia-Ukraine war, which started on Feb. 24, has met international outrage with the EU, United States and the United Kingdom, among others, imposing tough financial sanctions on Moscow.