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Ukrainian Foreign Minister Dmytro Kuleba on Wednesday rejected suggestions that his country should cede territory to Russia to help bring an end to their three-month conflict.
Responding to suggestions from experts such as former US secretary of state Henry Kissinger, Mr Kuleba said trying to appease Moscow was a failed policy that had done nothing to stop Russia invading Ukraine.
“If it failed once, it will fail twice,” he told the World Economic Forum in Davos, Switzerland.
“Even thinking rationally about this approach, I believe it’s flawed and it’s not going to work.”
Mr Kissinger said Ukraine should accept ceding some territory to Russia. But Mr Kuleba said: "He has his own opinion, but we strongly disagree with it. This is not something that we're going to do."
Ukraine has previously proposed giving the two countries 15 years to decide the future of the Crimean Peninsula, which was annexed by Russia in 2014.
Kyiv has said it is willing to accept neutrality outside Nato if it receives other security guarantees.
Mr Kuleba urged western powers to "kill Russian exports" because Ukraine’s economy was sustaining more damage from the war than Russia was from the barrage of international sanctions.
He said a tougher sanctions policy should include measures against the shipping industry to stop tankers from carrying Russian oil – one of the country’s most lucrative exports – around the world.
“The vast majority of Russian oil sold to the global market is carried by maritime means," Mr Kuleba said.
"If you tell the shipping industry that everyone carrying Russian oil anywhere in the world will face problems, this will be a big issue."
The US has banned Russian oil imports but the EU has so far failed to persuade all 27 of its members to approve an embargo. The bloc has not yet proposed a ban on Russian gas.
“As long as Russia makes money from oil and gas, their pockets are pretty full,” Mr Kuleba said.
“My message is very simple: kill Russian exports. Stop buying from Russia. Stop allowing them to make money that they can invest in the war machine that destroys, kills, rapes and tortures people in Ukraine."
He also rejected as “clear blackmail” a Russian proposal to unblock food exports from Ukrainian ports in return for sanctions being lifted.
Russian news agency Interfax quoted deputy foreign minister Andrei Rudenko as saying “a solution to the food problem requires a comprehensive approach, including the lifting of sanctions”.
The EU blames Russia’s bombardment of Ukrainian grain stores and the blockade of ships carrying grain and sunflower seeds for an escalating global food crisis.