On Tuesday, Ukrainian President Volodymyr Zelenskyy warned that Russia could begin building international support for a deal that could require Ukraine to make unacceptable compromises unless his nation wins a drawn-out battle in a key eastern city.
He invited the leader of China, long aligned with Russia, to visit.
The Ukrainian leader told the AP aboard a train shuttling him across Ukraine, to cities near some of the fiercest fighting and others where his country's forces have successfully repelled Russia's invasion.
The AP is the first news organisation to travel extensively with Zelenskyy since the war began just over a year ago.
Since then, Ukraine has surprised the world with the strength of its resistance against the larger, better equipped Russian military, backed by much of the West.
Ukraine's forces have held their capital, Kyiv, and pushed Russia back from other strategically important areas.
Zelenskyy is focused on keeping motivation high in both his military and the general Ukrainian population, particularly the millions who have fled abroad and those living in relative comfort and security far from the frontlines, as the war enters its second year.
Zelenskyy is aware that his country's success has been in great part due to the waves of international military support from the United States and western Europe.
But some in the US - including Republican Donald Trump, the former American president and current 2024 candidate - have questioned whether Washington should continue to provide Ukraine with billions of dollars in military aid.
Trump's likely Republican rival, Florida Governor Ron DeSantis, also suggested that defending Ukraine in a territorial dispute with Russia was not a significant US national security priority. He later made a statement after facing criticism from other corners of the GOP.
Zelenskyy did not mention the names of Trump or any other Republican politicians - figures he might have to deal with if they prevailed in the 2024 elections. He said that he worried that the war could be impacted by shifting political forces in Washington.
The United States really understands that if they stop helping us, we will not win, he said.
He sipped tea as he sat on a narrow bed in the cramped, unadorned sleeper cabin on a state railway train.