Trump's calls, Ukraine's strikes and Russia's barrage on Kyiv put markets on alert

The long-running Russia-Ukraine war appears to have entered a new phase after major developments over the weekend and ahead of a crunch NATO summit .

In the last 72 hours, U.S. President Donald Trump purportedly held separate calls with Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskyy , Ukrainian drones struck an oil terminal and port in St. Petersburg and the surrounding area and Russia launched its second large-scale attack on Kyiv in less than a week.

The prospect of renewed diplomacy, alongside the risk of escalation, has put investors on notice at a time when markets are trying to price geopolitical risk , energy security and the integrity of Europe's defense spending pledges.

"There is a real prospect to put an end to this war, and America's resolve is decisive," Zelenskyy said in a social media post on Saturday.

Ukraine's president said he'd discussed the latest situation on the frontline after more than four years of conflict and had agreed with Trump to continue talks at the NATO summit. Heads of state from 32 countries are expected in Ankara, Turkey's capital, from Tuesday for the two-day conference.

The Kremlin, meanwhile, said Sunday that Trump spoke with Putin for 90 minutes over the weekend, during which the U.S. president offered to help find a solution to the war.

Yury Ushakov, a Kremlin aide, described the conversation as "businesslike and very constructive," according to Russian state news outlet RIA Novosti .

"There are enormous prospects for mutually beneficial cooperation between our countries. To achieve this, Donald Trump emphasized, it would be necessary to end the Ukrainian conflict as soon as possible," Ushakov told reporters.

A White House spokesperson was not immediately available to comment when contacted by CNBC on Monday.

The U.S. president, who repeatedly said on the 2024 campaign trail that he could end the Russia-Ukraine war in one day if elected, has signaled the potential for renewed American support of Kyiv following the signing of an interim peace deal with Iran.

This suggestion, alongside a flurry of deep-strike successes by Ukraine, has prompted some analysts to conclude that the war could be shifting in Kyiv's favor, with Putin recently acknowledging the impact of Ukrainian drone strikes on Russian fuel production for the first time.

Ukraine has stepped up attacks on Russian oil facilities and military assets in recent weeks, seeking to cut off Moscow's energy revenues and try to raise the political pressure on the Kremlin.

Ukrainian officials reported that forces struck a major oil terminal in Russia's second-largest city, St. Petersburg, as well as the Kronstadt Naval Base, the main base of the Russian Baltic Fleet, on Friday and Saturday. The attacks reportedly caused fires at both the oil terminal and the military facility.

In response, Russian missiles and drones hammered Ukraine's capital in the early hours of Monday, killing at least 11 people and heavily damaging residential high-rise buildings, authorities said . The attack, which comes on the eve of the NATO summit, follows a separate deadly assault on Kyiv last week.

Researchers at the Institute for the Study of War (ISW), a Washington-based think tank, said Putin had sought to emphasize that Ukraine's European partners had a false perception of the battlefield realities, citing Ushakov's account of the call.

Instead, Putin was said to have told Trump about the "real" frontline situation in which Russian troops are advancing, with Putin claiming that Russian forces had seized the eastern town of Kostyantynivka.

Russia's claims of advance come as the Trump administration has increasingly spoken publicly about Ukrainian successes on the battlefield, including mid- to long-range attacks on Russian military assets and energy infrastructure, the ISW said in its latest assessment.