ISTANBUL, July 23 (Xinhua) -- Russian and Ukrainian delegations held a third round of peace talks here on Wednesday evening at the Ciragan Palace, during which the two sides agreed on another prisoner exchange but clashed on ceasefire terms and a potential presidential meeting.

Russian presidential aide Vladimir Medinsky and Secretary of Ukraine's National Security and Defense Council Rustem Umerov led the Russian and Ukrainian delegations, respectively. The closed-door talks were chaired by Turkish Foreign Minister Hakan Fidan.

Following the talks, which lasted for less than one hour, Umerov said at a press conference that Ukraine continues to insist on a full and unconditional ceasefire as the essential foundation for effective diplomacy.

"We are ready for a ceasefire now and to start substantive peace negotiations, and it is up to the other side to accept this basic step towards peace," Umerov said.

"We emphasize that the ceasefire must be genuine. It must include a complete cessation of strikes on civilian and critical infrastructure," he said.

Prior to the talks, Kremlin spokesman Dmitry Peskov said Tuesday that Moscow and Kiev are "diametrically opposed" in their positions on how to end the conflict, noting that "much work" still needs to be done.

The Ukrainian side has proposed to Russia to hold a meeting between Russian President Vladimir Putin and Ukrainian President Volodymyr Zelensky "by the end of August," where the participation of U.S. President Donald Trump and Turkish President Recep Tayyip Erdogan will be "especially valuable," he said.

During a separate press conference after the talks, Medinsky said Russia and Ukraine agreed to exchange 1,200 prisoners of war each, including a proposal from Moscow to swap about 30 civilians held by Ukraine in the Kursk region.

Russia has returned the bodies of 7,000 fallen Ukrainian soldiers and is ready to return 3,000 more, he said, requesting the return of any number of deceased Russian soldiers from Ukraine.

He also said that the Russian side proposed establishing three online working groups with Ukraine to address political, humanitarian, and military issues, and asked Ukraine to consider declaring short ceasefires of 24-48 hours along the contact line to evacuate the wounded soldiers and recover the bodies of fallen troops.

As to the Putin-Zelensky meeting Ukraine proposed, Medinsky said such a meeting is not being considered until certain processes are completed.

Meanwhile, Zelensky wrote on social media platform X after the talks that the ninth stage of prisoner exchange took place "today," which involved more than 1,000 people from the Ukrainian side, including those "seriously ill and severely wounded."

"It is important that the exchanges are ongoing," he wrote.

In his opening remarks to the talks, Fidan urged the two delegations to engage in result-oriented negotiations aimed at achieving a ceasefire and ultimately ending the war.

"Our goal is to end this bloody war, which has come at a heavy cost, as soon as possible," Fidan said.

While the previous two rounds of talks in Istanbul -- held on May 16 and June 2 -- led to the exchange of thousands of war prisoners and the bodies of fallen soldiers, they produced little progress toward a ceasefire.