The US is urging Ukraine to be open to peace talks with Moscow, with a senior Pentagon official saying Kiev’s forces would find it difficult to regain all the territory Russia seized in the war.

US Joint Chiefs Chairman Gen. Mark Milley said Wednesday that US and allied support has not waned, but added that Kiev’s success in fighting the Russian invasion puts it in a better position to start talks .

And last week Milley compared the current situation to World War I, when the two sides reached a standoff within months but fought for three more years at the cost of millions of lives.

He said Wednesday that the Russians are now increasing their grip on about 20 percent of Ukrainian territory and that front lines are stabilizing from Kharkiv down to Kherson.

“The probability of a Ukrainian military victory, defined as the expulsion of the Russians from all of Ukraine, including Crimea, the probability of this happening in the foreseeable future is militarily not high,” he said.

“There can be a political solution where the Russians withdraw politically, that’s possible,” Milley added.

“They want to negotiate from a position of strength. Russia is on its back at the moment,” he said.

White House national security spokesman John Kirby insisted Thursday that the United States is not trying to force talks on Kyiv or cede territory.

Only Ukrainian President Volodymyr Zelenskyy “is allowed to determine if and when he is ready for negotiations and what those negotiations will look like,” Kirby told reporters.

“No one from the United States is pushing, shoving, or pushing him to the table.”

But earlier this month, Zelenskyy dropped his stipulation that Russian President Vladimir Putin had to lose power before agreeing to talks — a postponement, the Kyiv Post reported, following pressure from the White House.

And on Monday, CIA Director William Burns held talks with Russian SVR intelligence chief Sergei Naryshkin in Ankara, the highest-level face-to-face meeting of US and Russian officials since the war began in February.

The details of their meeting remain classified, but Burns immediately flew to Kyiv to meet with Zelenskyy.

Burns “is not negotiating anything… We stand by our core principle: Nothing on Ukraine without Ukraine,” the White House said.

US support for Ukraine remains strong. This week, the White House asked Congress for an additional $38 billion to support Kyiv.

But it didn’t contradict Milley’s view either. Milley said in New York last week that Ukraine had lost nearly 100,000 battlefield dead and wounded – close to Russia’s estimated losses – and about 40,000 civilian casualties.

The number could multiply if Kyiv insists on fighting to the pre-2014 borders, he suggested.

From August to December 1914, the first months of World War I, a million people were killed, after which the front lines were cemented.

Yet neither side would negotiate, he said, and that “accounted for 20 million deaths by 1918.”

“So if there is an opportunity to negotiate, if peace can be achieved, seize it,” he said.

Milley’s comments raised fears that the United States was trying to roll back Kiev’s goal to retake all Russian-held country, including Crimea and Donbass, over which it lost control in 2014.

“Any idea expressed about our country’s concessions or our sovereignty cannot be called peace. Immoral compromises will lead to new blood,” Zelenskyy told the Halifax International Security Forum on Friday.

Professor Charles Kupchan of Georgetown University said the Biden administration is probably just trying to make sure the door is open for talks and that Milley is just “a little bit more forward-thinking.”

“I don’t think it’s premature. I think it’s wise. Russians and Ukrainians must have a perspective that there is a diplomatic path,” he said.

And it is also a signal to Zelenskyy, the sharpness of which is testing the patience of some allies.

“Zelensky understandably gets a little heated and says things that allies might not like,” Kupchan said.

Kupchan added that the White House is trying to deflect pressure from European allies to end the war before Kyiv is ready.

“The Biden administration wants to move slowly to ensure the transatlantic consensus remains rock solid.”

But defense strategy expert Frederick Kagan of the American Enterprise Institute said Milley does not reflect all of Washington.

Instead of pressuring Zelenskyy, the US should increase arms supplies to help Ukraine solidly defeat Russian forces, he said.

“I am not convinced that Ukrainians cannot reclaim all or most of their territory,” he said.

“We should help accelerate Ukrainian victory in this war,” he added. “Slowing down now is not the right thing to do.”