China’s Xi Jinping told President Trump that Russian strongman Vladimir Putin might end up regretting his decision to invade Ukraine, according to a new report.

Xi, one of Putin’s top allies, made the frank remark during his summit with Trump in Beijing last week while the two world leaders discussed the ongoing stalemate in Ukraine, sources told the Financial Times.

The admission comes as Russia struggles to make gains along the front lines, and Kyiv’s ever-growing drone strike capability forced Putin to scale back his World War II Victory Day military parade in Moscow earlier this month.

The war, now in its fifth year, has seen Russia’s invasion slow to a crawl as Ukraine’s defenses take out thousands of Moscow troops a week, as new and cheaper technological advances allow Kyiv to hold the front lines.

Ukraine has proved it can now launch long distance drone attacks at the Russian capital — and elsewhere inside Russia.

Putin has reportedly been forced to go into hiding as a result.

Kyiv also claimed that their new capability is why Putin was forced to agree to a cease-fire around Moscow’s Victory Day parade on March 9, which was the smallest it has ever been.

Putin is also facing massive economic pain across Russia as a result of the — with the Kremlin the spiking its value-added tax [VAT] last year by 2% to 22% to raise some $7.4 billion from small and medium-sized businesses.

The Russian president has also reportedly gone hat-in-hand to the country’s oligarchs, asking them to donate to his war fund.

Beijing, which has declared a “no-limits” partnership with Moscow, denied that Xi made such comments, and Kremlin spokesman Dmitry Peskov echoed the denial.

A White House readout of Xi and Trump’s meeting did not include any conversations about Putin or the war in Ukraine.

Along with discussing Ukraine, Xi reportedly spoke to Trump about the International Criminal Court, which has a warrant out for Putin’s arrest for crimes against humanity committed during the war.

During the talks, Trump reportedly told Xi that the US, China and Russia should band together to combat the ICC, claiming all three nations were aligned against the world agency.

The US does not recognize the ICC’s authority, and the Trump administration has previously slammed the world court for alleged politicization and over-reach, including after it issued a warrant against Israeli Prime Minister Benjamin Netanyahu over the war in Gaza.

Last year, Trump signed an executive order targeting people who work on ICC investigations of US citizens or allies, including Israel.

The White House declined to comment on Trump and Xi’s conversations on Russia.