US President Donald Trump has said Kyiv can win all of Ukraine back in its original form, marking a major shift in his position on the war with Russia.

In a post on his Truth Social platform, he said Ukraine could get back the original borders from where this war started with the support of Europe and NATO, due to pressures on Russia's economy.

His comments came after talks with Ukrainian President Volodymyr Zelensky, held after Trump had addressed the UN General Assembly in New York on Tuesday.

Trump has repeatedly expressed his desire to end the war, but has previously warned that the process would likely involve Ukraine giving up some territory, an outcome Zelensky has consistently rejected.

In his post, Trump added Ukraine could maybe even go further than that, but did not specify what he was referring to.

He also made no reference to Crimea, which was invaded and annexed by Russia in 2014. Russia launched its full-scale invasion of Ukraine in 2022.

Russian President Vladimir Putin's spokesman, Dmitry Peskov, suggested the reason for Trump's change of tone was that he had just talked to the Ukrainian president. The US president, he told reporters, had made the comments apparently under the influence of the vision put forward by Zelensky... this vision is in absolute contrast with our understanding of the current state of affairs.

The thesis that Ukraine can fight something back, we believe it erroneous. The situation on the front line speaks for itself.

Trump explained that his position had changed after getting to know and fully understand the Ukraine/Russia military and economic situation.

Putin and Russia are in BIG Economic trouble, and this is the time for Ukraine to act, he added, labeling Russia as a paper tiger.

The Kremlin spokesman responded by insisting Russia is in no way a tiger. It's more associated with a bear and there is no such thing as a paper bear, he told Russia's RBK Radio. He also denied Russia was in economic trouble, but conceded there were points of tension in some sectors linked to global sanctions.

Zelensky hailed the big shift in Trump's position, and speaking to reporters in the UN building, said he understood the US was willing to give Ukraine security guarantees after the war is finished.

Pressed on what this would look like, he added: I don't want to lie, we don't have specific details, but broached the possibility of more weapons, air defenses and drones.

Speaking later on Fox News, Zelensky said that Trump's Truth Social post about Ukraine's positioning surprised him but he took it as a positive signal that Trump and the US will be with us to the end of the war.

Earlier on Tuesday, following his speech to the UN, Trump also said NATO nations should shoot down Russian planes breaching their airspace, following a series of recent incursions by Russian fighter jets and drones.

Poland's foreign minister, Radoslaw Sikorski, responded on social media with a brief message of approval: Roger that.

Trump's Truth Social post represents an about-face after he spent most of the year insisting that Ukraine's situation was dire. In February, Trump told Zelensky during their fiery Oval Office exchange that he did not have the cards right now to prevail against a larger, more populous nation in a war of attrition.

Trump's comments suggest a potential shift in US support for Ukraine amidst ongoing military conflicts and geopolitics in the area.