By Christian Edwards, Svitlana Vlasova, Victoria Butenko, Gul Tuysuz and Anna Chernova, CNN

(CNN) — Russian and Ukrainian delegates met in Istanbul on Monday for their second set of direct peace talks, a day after Kyiv launched a shock drone attack on Russia’s nuclear-capable bombers, in an operation that President Volodymyr Zelensky said was a year and a half in the making.

The talks began late and lasted barely over an hour. Although both sides agreed to work on a new prisoner exchange, statements from the two sets of delegations suggested that little had been achieved to bridge the gulf between their positions, particularly on the matter of a ceasefire.

After the initial round of discussions in the Turkish city last month – the first between the warring countries since soon after Russia’s full-scale invasion in early 2022 – both sides agreed to share their conditions for a full ceasefire and a potentially lasting peace.

Russian state media agencies reported that Russia laid out two ceasefire “options” in its peace memorandum.

In the first option, Moscow will ask for the complete withdrawal of the Ukrainian Armed Forces (UAF) from Ukraine’s mainland Donetsk, Luhansk, Kherson, and Zaporizhzhia regions, RIA Novosti reported. Russia annexed those regions during its invasion in 2022, but has been unable to fully capture them in the years since.

In the second option, called a “package deal,” the UAF would have to demobilize, and all foreign military aid to Kyiv, including intelligence, would be halted, a summary of the memorandum published by RIA Novosti said.

Ukraine would also be prohibited from deploying and mobilizing its armed forces, and martial law in Ukraine would need to be lifted, with elections to be held no later than 100 days after it is lifted, the memorandum outlined.

It is not clear whether Ukraine can choose just one of the options, or whether it must agree to both.

The maximalist demands expand on the terms set by Russia during the 2022 trilateral talks held in Turkey.

In the past, Ukraine has refused Russian proposals for territorial concessions in exchange for peace.

Zelensky criticized Russia for not sharing its memorandum ahead of time. “Despite this,” he said before the talks began, “we will attempt to achieve at least some progress on the path toward peace.”

It is not yet clear if Ukraine’s daring Sunday air raid will streamline that path or make it more thorny. Kyiv has long sought to impress upon the Kremlin that there are costs to prolonging its campaign, but some analysts have warned that the operation – which struck Russian airfields thousands of miles from Ukraine’s borders – will only replenish Moscow’s resolve.

The mission, codenamed “Spiderweb,” was one of the most significant blows that Ukraine has landed against Russia in more than three years of full-scale war. Ukraine’s security service, the SBU, said it had smuggled the drones into Russia, hiding them in wooden mobile homes latched onto trucks. The roofs were then remotely opened, and the drones deployed to launch their strikes on four Russian airfields across the vast country.

Vasul Malyuk, the head of the SBU, said the attack caused an estimated $7 billion in damage and had struck 34% of Russia’s strategic cruise missile carriers – a total of 41 aircraft. These targets were “completely legitimate,” Malyuk said, stressing that Russia had used the planes throughout the conflict to pummel Ukraine’s “peaceful cities.”

The operation has provided a much-needed boost to morale in Ukraine, which has come under fierce Russian bombardment since peace talks began in mid-May, and is bracing for an expected summer offensive. Moscow launched a record 472 drones at Ukraine overnight into Sunday, only hours before the Ukrainian attack, according to Ukrainian officials.

At a summit in Lithuania on Monday, an upbeat Zelensky said the operation proved that Ukraine has “stronger tactical solutions” than Russia.

“This is a special moment – on the one hand, Russia has launched its summer offensive, but on the other hand, they are being forced to engage in diplomacy,” Zelensky said.

The talks in Istanbul were seen by many as a test of how genuine that engagement is. Last month, Russian President Vladimir Putin proposed holding “direct talks” with Ukraine in Turkey, but didn’t show up, despite Zelensky agreeing to meet. In the end, Moscow sent a low-level delegation to negotiate instead.

The second round of talks also failed to yield significant results. Rustem Umerov, Ukraine’s defense minister who headed its delegation, criticized Moscow for not sharing its memorandum ahead of Monday’s meeting.

Vladimir Medinsky, the head of Moscow’s delegation, said Moscow had given Ukraine a “very detailed and well-developed” document during the talks, which Kyiv would now study.

Whereas Umerov reiterated that Ukraine’s demand for an unconditional 30-day ceasefire has “remained unchanged for three months,” Medinsky said Russia had proposed a much narrower ceasefire, lasting just two or three days in “certain parts” of the frontline.

Zelensky insisted that Russia’s offer is “not a ceasefire.”

“What they are talking about is not a ceasefire, because meanwhile the war continues on the other areas of the front line, on all other areas and civilian infrastructure and civilians are being attacked,” Zelensky said in a press briefing on Monday.

Ukraine has insisted that a 30-day ceasefire is a test of whether Russia is serious about ending its war and is likely to view Moscow’s offer for a shorter truce as a ploy to rotate its combat units.

Seeking to speed up the peace process that Russia is keen to string out, Umerov said Ukraine had proposed a meeting between Zelensky and Putin by the end of this month.

“We firmly believe that all key issues can only be solved at the level of leaders,” Umerov said, suggesting that the leaders of other countries – such as US President Donald Trump – could also take part in the meeting.

Following the Istanbul meeting on Monday, Zelensky said that Turkish President Recep Tayyip Erdogan suggested a meeting between themselves, Putin, and Trump. Zelensky said he is open to such a meeting.

In the latest sign of his frustration that the war he pledged to end in a day is showing little sign of stopping, Trump said last week that Putin had gone “absolutely crazy,” after Moscow launched the largest aerial attack of the war.

Trump has repeatedly told Russia and Ukraine there will be consequences if they don’t engage in his peace process, although he has so far resisted growing calls from lawmakers in his Republican Party to use sanctions to pressure Putin into winding down his war.

Speaking in Lithuania, Zelensky said that if Monday’s meeting “brings nothing, that clearly means strong new sanctions are urgently, urgently needed.”