Sikorski, who also serves as deputy prime minister, spoke at the Warsaw Security Forum on Tuesday, days after Trump announced a deal with Russian President Vladimir Putin on diesel supplies.
The US leader wrote on Truth Social on Friday that he had held a "highly successful" call with Putin.
Trump said Russia had agreed to immediately deliver more than 300,000 tonnes of diesel to the US and global markets, followed by 500,000 tonnes in November and a further 1 million tonnes soon after.
Asked about the announcement, Sikorski noted that a Polish journalist had put the question to Trump in Washington, and the US president had replied that he had helped get Poland’s president elected.
"I'm counting on our MAGA president to use the friendship that he has with President Trump to do two things," Sikorski said: secure a permanent US military base in Poland, and explain to the American leader that "Putin is the aggressor and Zelensky is the victim of aggression."
"You end the war by persuading the aggressor to limit his level of ambition, not by asking the victim to capitulate."
German Foreign Minister Johann Wadephul, also on the panel, said Europe should "keep its course" and strengthen, not relax, sanctions on Russia, noting that the EU imposed measures on a further 1,600 individuals, companies and entities on Monday.
Norway’s Espen Barth Eide stressed that the war’s outcome would have far-reaching consequences for the future of European security.
"For our allies on the other side of the Atlantic, it is important to say that this is much more than an issue of Ukraine," Eide added.
Britain’s Foreign Secretary Ed Miliband pointed out that Russia had carried out more than 200 attacks on Ukrainian energy infrastructure in the past week, despite the "energy ceasefire" announced by Trump.
The speakers agreed that frozen Russian assets should be used to support Ukraine, while acknowledging the issue was not simple, partly because of objections from Belgium.
Sikorski said work was under way on a legal solution that would reduce the risk of future lawsuits from Russia.
He added that whenever it is suggested the frozen funds could be handed over to Moscow, he expects his answer, and that of other Western politicians, to be "over our dead bodies."
The officials said Russia was also trying to block Ukrainian grain shipments by sea, with effects well beyond Europe, and using air strikes on civilians to try to break Ukrainians’ morale.
Sikorski told the panel this was failing, while Ukraine was successfully hitting Russian refineries.
He added, however, that Putin still had cards to play and that the course of the war would become clearer around the middle of next year.
(ał)
Source: PAP