President Trump and the Ukrainian president meet in person for the first time; chief White House correspondent John Roberts reports from New York.
“It wasn’t explained to me," Zelensky said about the withholding of the support from July until Sept. 11. Trump has cited corruption in Ukraine as one of the reasons the U.S. held back the funds.
Zelensky pushed back against allegations that Trump used military aid as leverage during the leaders' July 25 call. Trump has been accused of taking part in an alleged quid pro quo scheme centered on that call, in which he sought to have Ukrainian officials investigate leading presidential campaign rival Joe Biden, Biden's son Hunter and their business dealings in the country. The accusations have sparked an impeachment inquiry into Trump.
“It is impossible to put pressure on me,” Zelensky said on Tuesday, addressing the allegations. “Many people try to influence me, [but] I am the president of independent Ukraine.”
Zelensky said during a bilateral meeting with Trump at the United Nations General Assembly last week that their call was "great" and "normal," and that "nobody pushed me."
Trump has been dismissive of claims he tried to use the frozen military aid as leverage, calling his call with Zelensky "perfect" and a "no-pressure" conversation. He has written off the Democrats' impeachment probe "another witch hunt."
A transcript of the Trump-Zelensky call was released last month. It shows that while Trump sought a Ukrainian probe into the Biden family, he did not explicitly connect the aid to that effort.
House Democrats launched an impeachment inquiry into Trump over the allegations following an initial whistleblower complaint that accused Trump of "using the power of his office to solicit interference from a foreign country in the 2020 U.S. election."
Trump on Tuesday night said that what is taking place is "not an impeachment, it is a coup."
It's "intended to take away the power of the people, their vote, their freedoms, their Second Amendment, religion, military, border wall and their God-given rights at a citizen of the United States of America," he tweeted.
Later Tuesday night, Trump tweeted: "The Greatest Witch Hunt in the history of our country!"
The Defense Department announced $250 million in aid to Ukraine on June 18. Trump had the now-controversial call with Zelensky the following month, on July 25.
A month after that, on Aug. 26, the whistleblower complaint was forwarded to Acting Director of National Intelligence Joseph Maguire.
On Sept. 10, House Intelligence Committee Chairman Rep. Adam Schiff, D-Calif., made a formal request to transmit the whistleblower complaint concerning the president's Ukraine call to the committee.
The funds were released to Ukraine on Sept. 11. Defense officials say $225 million has been allocated to date.
The funds are of great importance to Ukraine, which faces an ongoing push from Russia in the eastern part of the country. Ukraine has been engaged in fierce ground combat there with Russian and Russian-backed forces, including armored units, for the past five years.
Fox News' Lucas Tomlinson and The Associated Press contributed to this report.