On Sunday, Trump declared an energy truce between Russia and Ukraine, though hostilities have continued in the period since, according to reports. A post on Truth Social carried the president's announcement that negotiators from both parties had arrived at a mutual commitment to halt strikes on energy infrastructure. The president accompanied that message with a terse directive to the parties concerned — "Do not break it!"

A separate development on Friday had him announcing an agreement to procure hundreds of thousands of tons of diesel from Russia. Uncertainty over whether the truce declaration will hold has deepened, with both Russia and Ukraine reported to have been caught off guard by the announcement.

Missile strikes hit Kharkiv within hours of the announcement being made. Zelensky's office indicated that drone strikes and glide bombs had been directed at an energy installation within the city.

A statement from Zelensky on Monday laid out his position on where the deal currently stands. Zelensky put forward a conditional position, indicating that any absence of Russian agreement on an energy ceasefire would draw a response from Ukraine's side. The statement specified that long-range attacks on oil infrastructure would continue unless strikes against the energy grid and civilian population were brought to a halt, according to the speaker's terms.

Whether any formal arrangement has been reached between the two sides remains unconfirmed by the Kremlin. On Monday, the Kremlin's spokesperson, Dmitry Peskov, indicated that dialogue was ongoing and that further details would be shared once there was something concrete to report. Responding to a direct question about a potential 60-day ceasefire tied to Ukrainian elections, Peskov said Russia's objective was lasting peace rather than a temporary halt to hostilities.

Separately, the administration in Washington had been urging Kyiv to stop conducting long-range strikes against Russian oil refineries, citing the effect those operations had on global energy markets. In a public statement, Trump directed a pointed demand that the individual in question bring the conduct to an immediate halt. Backing that position, the administration has reportedly placed under consideration a halt to intelligence-sharing arrangements and a suspension of the Prioritised Ukraine Requirements List, a procurement channel through which US weapons are obtained.

Diplomats from Europe indicated that Washington had been pressing multiple governments to halt strikes on oil-refining infrastructure. Analysts note that any follow-through on those threats would place Patriot interceptor missile supplies among the first areas to feel the effects in Ukraine.

Investor sentiment landed on neither side of a clear divide once the announcement circulated through trading floors. On Monday morning, a 0.6 per cent fall took Brent crude to around $104 a barrel, with traders reacting to the possibility that sanctions on Russian oil could be loosened. London's FTSE 100 index edged upward by half a percentage point.

Drawing on his Deutsche Bank research role, Reid characterised the arrangement as untested rather than operational, pointing to a comparable breakdown the previous month as context for that assessment.

Speaking to reporters, Kallas — who holds the EU's foreign affairs portfolio — outlined the bloc's openness to a ceasefire, on the condition that any such agreement would be durably observed. No proof had yet reached the EU, she noted, that Russia plans to honour the terms of the deal. Her position was that any genuinely balanced arrangement would need to cover a broader range of energy infrastructure, since limiting the terms to oil refineries alone tilts the playing field toward Russia, whose refining capacity across that sector substantially exceeds Ukraine's.

No statement addressing the reported threats to withhold military and intelligence support came from administration officials.