Donald Trump says he will meet Ukrainian President Volodymyr Zelenskiy, having criticised him on the US campaign trail and expressed doubts about Ukraine's ability to win its war with Russia.
Trump, the Republican candidate in the November 5 presidential election, made the announcement on Thursday, just hours after Democratic President Joe Biden announced more than $US8 billion ($A12 billion) in new military aid for the US ally.
Zelenskiy has long sought a meeting with Trump. The two men spoke by phone in July, but have not met in person since Trump's term as president ended in 2021.
During a press conference on Thursday, Trump repeated his claims that he could rapidly negotiate a deal between Russia and Ukraine if he defeats Biden's vice president, Kamala Harris, the Democratic candidate in the race for the White House.
"President Zelenskiy has asked to meet with me, and I will be meeting with him tomorrow morning at around 9:45 in Trump Tower" in New York, Trump said.
Asked by a reporter if Ukraine might have to give up any of its territory to reach a peace deal with Moscow - a non-starter for Kyiv - Trump did not rule it out.
"We'll see what happens," he said.
Shortly before Trump's comments, Harris pledged support for Ukraine and - in a veiled reference to Trump - said those who would have Ukraine swap land for peace with Russia were supporting "proposals of surrender".
Harris was speaking alongside Zelenskiy at the White House, a day after Trump assailed him for not making a deal with Russia that Trump said could have ended the war and shortly after the White House announcement of the new aid package.
It was Harris' seventh meeting with Zelenskiy and the third this year.
Earlier in the week, Trump looked poised to reject Zelenskiy's meeting request.
The Ukrainian leader had said before departing for New York for the annual UN General Assembly that he hoped to present his "victory plan" to win the war with Russia to Harris, Trump and Biden.
But he upset Trump's campaign after visiting a munitions factory over the weekend in the battleground state of Pennsylvania with that state's governor, Josh Shapiro, a Democrat and a Harris ally.
Trump has stood by his criticisms of Zelenskiy on the campaign trail. He said on Monday that Zelenskiy wanted Harris to win the election, and on Wednesday he called the Eastern European nation "dead" and "demolished".
The US aid announced by Biden includes the first shipment of a precision-guided glide bomb called the Joint Standoff Weapon, with a range of up to 130 km.
The medium-range missile gives Ukraine a major upgrade to the weapons it is using to strike Russian forces, allowing the Ukrainians to do it at safer distances.
Biden also said he would order the Pentagon to expand training of Ukrainian F-16 pilots, including by supporting the training of an additional 18 pilots next year.
