The G7 leaders on Tuesday wrapped up their Ukraine-heavy summit by saying they would look into capping the price of Russian oil, but stopped short of a full agreement on new sanctions.
An American-led push to squeeze the Kremlin's oil revenue resulted in only a tentative agreement that the idea would be explored further after the three-day summit in Germany.
A proposal by French President Emmanuel Macron to widen the price cap beyond Russia, to ease the pain for consumers of soaring energy prices, has also been parked for further discussions.
Summit host Chancellor Olaf Scholz of Germany nonetheless said the club of rich democracies would continue to "drive up the economic and political costs" of the conflict in Ukraine that overshadowed the talks in the Bavarian Alps.
The summit played out against the backdrop of rocket strikes on Kyiv and a deadly explosion at a shopping centre in Kremenchuck condemned as an "abominable attack" by the G7 leaders. President Volodymyr Zelenskyy told them to put Ukraine in a winning position by winter.
Leaders promised to maintain support for Ukraine and Mr Macron said he hoped the war could be over this year, but said more work was needed on a price cap before sanctions can be tightened further.
The idea of a price cap is that western powers would throw their economic weight around to stop Russian oil from sailing the world if it is being sold for too high a price.
Tankers with cargoes that flout the price cap would be denied shipping insurance and other services - preventing Moscow from having the last laugh if it can sell its reduced oil exports at runaway prices.
Mr Macron said leaders could not "push a button" and make this happen overnight and said a "coalition of buyers" going further than the G7 - which consists of the US, Canada, Britain, France, Germany, Italy and Japan, plus the European Union - was needed to implement it.
“At leaders’ level, there is an agreement to look into this and to try to make it work. Then we will see what’s feasible,” said an official close to the talks.
Jake Sullivan, the national security adviser to US President Joe Biden, said discussions had begun with India - one of the countries which attended the G7 summit as a guest - on how a price cap would work.
Mr Biden's Treasury Secretary Janet Yellen said it was a "significant step" that G7 leaders had agreed to explore the idea and said Washington would "work expeditiously... to advance this effort".
The 28-page text adopted by leaders after three days of negotiations said the objective was to cut Russian revenue and that, even aside from the war in Ukraine, high energy prices "threaten our shared prosperity".
"We welcome the decision of the European Union to explore with international partners ways to curb rising energy prices, including the feasibility of introducing temporary import price caps where appropriate," it said.
"As for oil, we will consider a range of approaches, including options for a possible comprehensive prohibition of all services, which enable transportation of Russian seaborne crude oil and petroleum products globally, unless the oil is purchased at or below a price to be agreed in consultation with international partners."
Leaders also discussed the possibility of limiting prices on gas, which is mainly transported from Russia by pipeline — meaning western countries would simply name their price.
An EU said it was “two different stories” with oil and gas, because Europe has made more progress in banning oil and it largely arrives by sea rather than pipeline. The question of how the Kremlin would react to any price cap has also been raised in discussions.
Any EU price cap on oil would involve reopening talks on sanctions that only recently concluded, after weeks fractious negotiations with Hungary and other landlocked countries.
However, officials believe that only technical adjustments to a sanctions package would be needed and say the principle of aiming at oil shipments, as opposed to pipelines, had already been agreed upon.
The aim of the sanctions is to curb one of Russia's most lucrative sources of revenue and free European countries from the awkward position of paying Moscow for energy while condemning it over the war.
However, the G7 leaders have struggling voters to think about and there are concerns over whether sanctions will last when winter bites.
After three days of talks in which western leaders sought to show leadership amid geopolitical, energy, food and climate crises, the wealthy countries promised to put $4.5 billion of new funding towards tackling global hunger.
They endorsed the principle of an international “climate club” backed by German Chancellor Olaf Scholz, the host of the Alpine summit, but disappointed activists by including loopholes in their language on fossil fuels.
Mr Scholz said the three key messages from the summit were “full support for Ukraine, the joint fight against global famine and more ambition in climate protection”.
The leaders said in a separate declaration on Ukraine that they would support the country for "as long as it takes".
"There is only one way out: for Putin to accept that his plans in Ukraine will not succeed," said summit host Chancellor Olaf Scholz of Germany.
But Mr Macron wants to bring oil prices down and had floated the idea of applying the price cap to countries other than Russia.
"We all have a situation on our countries which is unacceptable," said Mr Macron, who described the cost of living crisis as unsustainable because of the money needed to ease pressure on consumers.
He suggested high prices could lead to instability and social unrest - a problem well known to Mr Macron after discontent over fuel costs mushroomed into the broad "yellow vest" protests against his government in 2018 and 2019.
Leaders said in the statement that they encouraged oil exporters to increase production to "decrease the tension in energy markets".
From the summit venue in Germany, Mr Macron spoke on Monday to UAE President Sheikh Mohamed bin Zayed.
Suhail Al Mazrouei, the UAE's Minister of Energy and Infrastructure, was quoted by state news agency Wam as saying: "The UAE is producing near to our maximum production capacity based on its current OPEC+ production baseline, which the UAE is committed to until the end of the agreement."
