His remarks came as Ukraine withdrew from the strategic eastern city of Avdiivka, sealing Russia’s most significant territorial victory since capturing Bakhmut last spring and as opposition leader Alexei Navalny’s death put renewed focus on President Vladimir Putin’s brutal repression of dissent.

Adding to the unease at the annual Munich conference, former president Donald Trump a week ago suggested he would encourage Russia to attack NATO countries if they do not spend enough on defense, deepening questions about American reliability in the years ahead.

Ukraine withdraws from Avdiivka as Russia advances into strategic city

In Munich, top U.S. officials, including Vice President Harris and Secretary of State Antony Blinken have tried to reassure allies — though it is not clear if it has worked, given the uncertainty of the U.S. election in November and President Biden’s low poll numbers.

Questions about the deadlock in Washington over aid to Ukraine — and about U.S. global leadership more broadly — have dominated the annual conclave.

In his speech, Zelensky referenced critical shortages of ammunition. He noted, dryly, that unlike politicians in the West, Putin is moving quickly. “Please, everyone, remember that dictators do not go on vacation,” he said.

Zelensky tried to make clear the stakes without directly calling out U.S. officials. When asked by CNN’s Christiane Amanpour what he would say to the Republicans blocking Ukraine aid, Zelensky quipped “Is this being shown on television now?” Then, he said he would not comment.

Navalny team confirms death and demands authorities return body to family

The Ukrainian leader, known for fiery speeches and direct appeals, took the time to politely acknowledge U.S. support so far Ukraine — and to invite a certain Republican presidential candidate to make a visit.

Trump’s threat against NATO allies that underspend on defense was just his latest utterance to cause anxiety in Kyiv. The former president has also claimed that he could settle the war within a day — an assertion that has alarmed supporters of Ukraine who fear Ukraine would be forced to surrender large swaths of sovereign territory.

Zelensky said he would be pleased to work with Trump — and also to show him around. If he comes to Ukraine, Zelensky said: “I am ready to go with him to the front line.”