European Union leaders are unlikely to strike a deal on an oil embargo against Russia at their summit next week, according to the President of the European Commission, Ursula von der Leyen.
A special meeting of the European Council will take in Brussels next Monday and Tuesday.
"I don't think the summit is the right place for that... we should not stare at the summit," she told Reuters on the sidelines of the World Economic Forum in Davos, Switzerland.
She added that negotiations with member states were ongoing.
Ms von der Leyen's Commission has proposed phasing out Russia noil imports by the end of the year in most EU member states, while Hungary and others could be given more time.
It would be the EU's harshest sanction yet in response to Moscow's 24 February invasion of Ukraine.
Hungary, however, has so far refused to lift its veto.
It said hundreds of millions of euros are needed to upgrade its refining and pipeline infrastructure so that it can cut out Russian oil, while a total modernisation of its energy system would cost billions of euros.
Von der Leyen said the negotiations were mainly focusing on working out details now: "I don't think that this will be atopic at the Council that will be decided there".
She was echoed by an EU official.
"There is no way that such a technical subject could be negotiated by the heads of state and government at the summit," the official said.
Earlier, Ms von der Leyen called for talks with Moscow on unlocking wheat exports that are trapped in Ukraine as a result of a Russian sea blockade.
"It can't be in Russia's interests that - because of Russia - people are dying of hunger in the world," she said at Davos.
"Therefore I think we should first of all look at the dialogue with Russia, whether there is not an agreement that this wheat gets out of Ukraine."
US Secretary of State Antony Blinken last week accused Russia of using food as a weapon by holding "hostage" supplies - not just for Ukrainians, but also millions of people around the world.
Moscow rejects this allegation.
"The most important (thing) is to deblock the Black Sea. This is a call on Russia," Ms von der Leyen said in Davos.
She said a food crisis was approaching at full speed and some sort of dialogue with Moscow was needed to unlock 20 million tonnes of wheat stuck in Ukraine.
At present, some Ukrainian grain produce is being carried by road to surrounding countries for export - most notably via Constanta in Romania.
Ursula von der Leyen said "global cooperation" was the "antidote to Russia's blackmail".
"In Russian-occupied Ukraine, the Kremlin's army is confiscating grain stocks and machinery.
"And Russian warships in the Black Sea are blockading Ukrainian ships full of wheat and sunflower seeds," she added.
Russia's invasion of Ukraine - and the West's attempt to isolate Moscow as punishment - have sent the price of grain, cooking oil, fertiliser and energy soaring.
The Kremlin said yesterday it was the West that was responsible for the global food crisis by imposing the severest sanctions in modern history on Russia over the war in Ukraine.
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Ms Von der Leyen also said that Kyiv must win the war it is fighting against Moscow, making the invasion of Ukraine a strategic failure for Russia's President Vladimir Putin.
At the World Economic Forum that gathers more than 2,000 business and political leaders as well as experts at the Alpine resort, she described Moscow's playbook as coming straight from another century.
Russia is "treating millions of people not as human beings but as faceless populations to be moved or controlled or set as a buffer between military forces, trying to trample the aspirations of an entire nation with tanks," she said.
"Ukraine must win this war, and Putin's aggression must be a strategic failure," she added.