"This fall will determine the future of this war," he said in a post on X alongside his nightly video address, delivered from his plane.
Zelenskiy made an unannounced stop in President Joe Biden's hometown of Scranton, Pennsylvania to visit a munitions plant which he said was ramping up manufacture of crucial 155-mm artillery shells to help the Ukraine war effort.
We have arrived in the United States. The main objective is to strengthen Ukraine and protect all our people. This war can only be ended with a just peace through global efforts. Everyone who values life can help, and the most effective help is determination. Ukraine's Victory… — Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) pic.twitter.com/nQvqXj8tDOSeptember 22, 2024
"It is in places like this where you can truly feel that the democratic world can prevail," Zelenskiy said in a post on X, alongside photographs of him thanking plant workers.
The Ukrainian leader's concerns about a shortage of such munitions have taken on added urgency as Russia pummels Ukraine's energy grid ahead of the critical winter months.
In his video address, Zelenskiy said Ukraine was doing everything it could, by acquiring weapons and through diplomacy, "to consolidate our partners' support and force Russia into peace".
Zelenskiy flew on to New York, where he was expected to meet heads of US companies to discuss his country's energy needs as well as leaders of states and international organisations.
Zelenskiy's visit coincides with US efforts to prepare a $US375 million ($A551 million) military aid package for Ukraine, breaking a months-long trend toward smaller packages for Kyiv's military operations.
Zelenskiy said he would present a "victory plan" in Ukraine's war against Russia first to Biden. He is also expected to discuss the plan with Vice President Kamala Harris in a separate meeting on Thursday, as well as with other world leaders.
Zelenskiy also hopes to meet Republican presidential candidate Donald Trump, who has called US aid to its eastern European ally a waste of money and has declined to say he wants Ukraine to win.
Trump faces Harris in the November 5 US election.
US officials told Reuters an aid package, expected to be announced this week, includes patrol boats, additional ammunition for high-mobility artillery rocket systems (HIMARS), 155- and 105-mm artillery ammunition, spare parts and other weapons.
Zelenskiy will speak at a UN summit on Monday, participate in Security Council meetings on Ukraine on Tuesday and speak during the General Assembly on Wednesday.
