WASHINGTON/MOSCOW - Ceasefire negotiations between Russia and Ukraine "will begin immediately," said US President Donald Trump after his two-hour call Monday with his Russian counterpart, Vladimir Putin, depicting "the tone and spirit of the conversation" as "excellent".

Upbeat as he is, the talk remains "inconclusive," with little sign of a breakthrough, said US media, as the timing, location and participants of any negotiations remain unclear. Meanwhile, his friendly posture toward Putin has made Kyiv wary and Europe frustrated. Moscow's cooler tone further adds to doubts over any upcoming ceasefire, as analysts see widening gaps in positions among the stakeholders.

US upbeat, Russia restrained

Right after his phone call with Putin, Trump posted on the social platform Truth Social that Russia and Ukraine will "immediately start negotiations toward a ceasefire," and work to end the conflict.

He said Russia is eager to pursue major trade deals with the United States once the conflict ends. "There is a tremendous opportunity for Russia to create massive amounts of jobs and wealth. Its potential is UNLIMITED. Likewise, Ukraine can be a great beneficiary on Trade, in the process of rebuilding its Country."

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He added that the ceasefire conditions will be negotiated between Russia and Ukraine, "as it can only be, because they know details of a negotiation that nobody else would be aware of."

In contrast to his enthusiasm, Putin offered a more cautious response, saying only that Russia "is ready to work with the Ukrainian side on a memorandum on a possible future peace accord," and stopped short of agreeing to an immediate ceasefire. And his aide Yury Ushakov confirmed that a ceasefire timeframe was not "discussed."

Although Putin called the conversation "frank, informative and constructive" and thanked Trump for his diplomatic efforts, he signaled that Moscow's core demands remain unchanged. "I would like to note that, in general, Russia's position is clear. The main thing for us is to eliminate the root causes of this crisis," Putin said.

Meanwhile, Kremlin spokesman Dmitry Peskov said that if the United States can "help achieve our goals through peaceful means, then this is indeed preferable."

The Atlantic, an American magazine, said in a Monday article that Putin would "almost certainly never accept an unconditional ceasefire, which would leave significant issues unresolved, such as territorial disputes and Ukraine's security guarantees."

The hope of an immediate ceasefire is further dimmed as Trump warned that he could back out of the negotiation process when speaking to reporters later. "Big egos involved, but I think something's going to happen. And if it doesn't, I just back away, and they're going to have to keep going again," he said.

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After falling short on his campaign promise to quickly end the Ukraine crisis, the Trump administration has repeatedly warned that it may withdraw from its mediation efforts if there is no progress toward ending the conflict.

US Vice President JD Vance reiterated such warnings ahead of Trump's call with Putin. "We realize there's a bit of an impasse here ... The United States is not going to spin its wheels here. We want to see outcomes," he said.

"I'm not sure that Vladimir Putin has a strategy himself for how to unwind the war," Vance added. Trump later told reporters that he believed Putin was serious about wanting peace.

Kyiv unsettled, Europe disappointed

Trump said he informed European leaders and Ukrainian President Volodymyr Zelensky right after the call. According to Bloomberg, Zelensky and his European allies believed they had secured a commitment from Trump to impose fresh sanctions on the Kremlin if Putin refused to observe a ceasefire on Monday, but no such action has followed.

In response to the Putin-Trump call, Zelensky said Monday that he spoke to Trump twice, before and after the phone call. "I reaffirmed to President Trump that Ukraine is ready for a full and unconditional ceasefire," he said on the social platform X, highlighting that it is crucial "not to dilute this proposal."

"I also reiterated that Ukraine is ready for direct negotiations with Russia in any format that brings results," he said. "It is not necessary to convince Ukraine, and our representatives are prepared to make real decisions in negotiations."

"It is crucial for all of us that the United States does not distance itself from the talks and the pursuit of peace," he added, calling for further sanctions if Russia "refuses to stop the killings."

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One day ahead of the Putin-Trump call, Russia launched what Ukraine said was its largest drone attack since the conflict began. After a night of air raid alerts, Ukraine's air force said Sunday morning that Russia had launched 273 drones at Ukrainian cities, surpassing the previous record set in February on the third anniversary of the war.

Following the phone call, clear differences in the approach between Washington and Europe are emerging, the Frankfurter Rundschau, a German newspaper, reported Tuesday.

While Trump depicted Russia as an economic partner, Europe stressed the need to "increase pressure on the Russian side through sanctions" if it refuses to accept a 30-day unconditional ceasefire proposed by Trump and backed by Ukraine and Europe, said the report.

According to Bloomberg, several European countries were "shocked" that Trump did not want to push Putin with sanctions, and have aired their disappointment after being briefed by Trump following his phone call with Putin.

Ursula Schrode, professor of Political Science at the Institute for Peace Research and Security Policy, said that the sanctions are especially significant amid the bloc's growing fatigue and frustration towards Trump's stance on the negotiation process.

"One of the greatest risks now is a complete US withdrawal from the peace process, leaving the EU to bear full responsibility," she said.

Elusive ceasefire, rising tension

Despite Trump's flurry of phone calls, there is no sign that any side has softened its stance, but a sniff of rising tension in the air, as all sides double down on irreconcilable demands.

As Russia doubles down on its stance that a ceasefire is only possible if Ukraine abandons its aspirations for closer ties with the West, it argues that an early truce would merely offer a breather to a weakened Ukraine.

Yuri Svetov, a Russian political analyst, said the peace Kyiv seeks is fundamentally at odds with the lasting security Moscow demands. Meanwhile, Michael Kofman, senior fellow at the Carnegie Endowment for International Peace, noted that under current battlefield conditions, Moscow lacks "strong incentives" to agree to a ceasefire.

Europe, on the other hand, grew increasingly doubtful of Trump's self-crafted image as a master dealmaker as he failed to deliver any meaningful concessions from Moscow.

"Putin has been emboldened by his ability to make maximalist demands of Ukraine without experiencing any serious pushback from the Trump administration," said Bota Iliyas, a senior analyst at Prism, a strategic intelligence firm in London.

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Echoing her view, French Foreign Minister Jean-Noel Barrot said Europe can not afford to wait for Trump.

"Of course, it would be helpful if the United States slammed its fist on the table -- if that much-discussed sanctions package presented by the senators could be adopted," Barrot said. "But without waiting for the US to act, let us take responsibility ourselves."

The EU adopted Tuesday a fresh package of sanctions on Russia, including blacklisting some 200 oil tankers used to circumvent curbs on Russian oil exports as the bloc threatens further punishment if Moscow does not agree to a Ukraine ceasefire.

Earlier Tuesday, Britain also announced its sanctions without waiting for Washington to join them, targeting dozens of entities.

EU High Representative for Foreign Affairs and Security Policy, Kaja Kallas, said, "I do not think we have a choice. We need to put more pressure."

"We want to see those consequences also from the US side. We really haven't seen the pressure on Russia from these talks," she added.