Ukraine’s top general has warned there will be no quick “breakthrough” in the counteroffensive against Russia, comments that will create consternation for Joe Biden as he battles to ensure the US maintains its funding for Kyiv.

In a stark assessment delivered 18-months after Vladimir Putin launched his invasion, Ukraine Gen Valery Zaluzhny said both sides had reached an effective stalemate.

Five months after Ukraine forces, with the backing of Nato arms and know-how, sought to drive back Russian forces, his troops have managed just 10 miles.

“Just like in the First World War we have reached the level of technology that puts us into a stalemate,” the general told The Economist.

He said it would require a massive technological leap to break the deadlock. “There will most likely be no deep and beautiful breakthrough.”

To those who closely follow the conflict, not least the people of Ukraine, where last week protesters gathered to call for shorter deployments for soldiers, the statement will not come as a surprise.

Yet to those who had thought the long-touted counteroffensive could quickly repel Russian forces and force them from Ukrainian territory, it may well do.

After the head of the Wagner Group mercenaries, Yevgeny Prigozhin, appeared to call for an end to the conflict this summer and turned his fighters towards Moscow, it appeared Putin’s plans had turned to chaos.

When Prigozhin subsequently died in a plane crash in August, allegedly at the orders of Putin, it was perhaps a sign the Russian leader was trying to take a new grip on what was happening.

Ukraine’s army should have been able to push back at a pace of 18 miles a day as it breached Russian defensive lines, the general said.

“If you look at Nato’s text books and at the maths which we did [in planning the counter-offensive], four months should have been enough time for us to have reached Crimea, to have fought in Crimea, to return from Crimea and to have gone back in and out again,” Gen Zaluzhny told the magazine.

When his troops got nowhere, he wondered if it was his commanders, so he changed them. They still had no luck.

He said he only got an insight when he reread a book published in 1941 by a Soviet major-general, who analysed the battles of the First World War. It was called “Breaching Fortified Defence Lines”.

He said: “And before I got even halfway through it, I realised that is exactly where we are because just like then, the level of our technological development today has put both us and our enemies in a stupor.”

It is estimated that while up to 70,000 Ukrainians have been killed and 100-120,000 injured, Russia’s casualties stand at an estimated 120,000 deaths.

For all those deaths, Russia currently controls 20 per cent of Ukraine territory.

Gen Zaluzhny initially believed he could halt Russia “by bleeding its troops”. He added: “That was my mistake. Russia has lost at least 150,000 dead. In any other country such casualties would have stopped the war.”

The 49-year-old, known to friends as “Our Valera”, told The Economist: “Let’s be honest, it’s a feudal state where the cheapest resource is human life. And for us…the most expensive thing we have is our people.”

The comments from the general, appointed Commander-in-Chief of the Ukrainian military in July 2021, will not be much celebrated in the White House.

Following Russia’s invasion, Mr Biden earned plaudits for standing firm with Ukraine leader Volodymyr Zelensky, cementing the support of Nato’s other members, and encouraging nations outside the alliance to offer support and funding to its war effort.

Mr Zelensky has repeatedly resisted any calls to hand over Ukraine territory and insisted his country is involved in an existential fight.

Increasingly Mr Biden, who has spearheaded as much as $75 billion in assistance to Ukraine, has pitched himself as a defender of democracy, even as the likes of Donald Trump, has said the US should stop funding the war. 

Mr Trump’s calls have been taken up by many in the Republican Party, not least new Speaker Mike Johnson, who have said the money should instead be spent on the US’s border with Mexico to stop illegal immigration.

In the aftermath of Hamas’s attacks on Israel, some said the money being spent in Ukraine could instead go to Israel.

Indeed, while Mr Biden has sought to tie funding for both nations, Mr Johnson has put forward a bill that would split the two, and pin money for Ukraine with spending cuts. So far, that bill has made little progress.

Earlier this week, Mr Biden’s top diplomat, Secretary of State Antony Blinken, pleaded with legislators to keep the funding bill linked.

“The conflicts in Ukraine and the Middle East have clear links,” he told Senators on Capitol Hill. 

“Since we cut off Russia’s traditional means of supplying its military, it’s turned more and more to Iran for assistance. In return, Moscow has supplied Iran with increasingly advanced military technology, which poses a threat to Israel’s security.”

Gen Zaluzhny said it would take something extraordinary to lever a breakthrough.

“The simple fact is that we see everything the enemy is doing and they see everything we are doing,” he told the magazine.

“In order for us to break this deadlock we need something new, like the gunpowder which the Chinese invented and which we are still using to kill each other.”