The US has been helping Ukraine step up its long-range strikes on Russian energy targets in an attempt to weaken Vladimir Putin’s war effort and force him to negotiate.

For months, Washington has provided Kyiv with the intelligence needed for its intensifying aerial offensive against critical Russian refineries, pipelines and power stations, according to Ukrainian and US officials.

The intelligence-sharing, the officials told the Financial Times, has been crucial to helping Ukraine carry out the attacks since midsummer that have driven up domestic prices, cut Russian oil refining by a fifth on certain days, and led to a reduction in exports from key ports.

It is the first time Washington has been reported to have directly supported air strikes on energy facilities deep inside Russian territory – a move discouraged by the Biden administration over concerns of escalation.

The shift is viewed as a further signal of Donald Trump’s growing support for Kyiv and hardening stance towards Moscow, particularly in the wake of his failed summit with Putin in Alaska in August.

On Saturday, Volodymyr Zelensky, the Ukrainian leader, called on the US president to help broker peace in Ukraine “as he did in the Middle East”, after Israel and Hamas signed the first phase of a US-led peace deal, saying if Mr Trump could stop one war, “others can be stopped as well”.

The pair spoke again on Sunday, with Mr Zelensky hailing another “productive” conversation that included “long-range capabilities” – a suggestion that Tomahawk missiles might have been on the agenda.

“We covered all the aspects of the situation: defence of life in our country, strengthening our capabilities in air defence, resilience, and long-range capabilities,” he said in a statement, adding that Mr Trump was “well-informed”.