America’s top military commander has said the credibility of the US has been damaged as a result of the chaotic withdrawal from Afghanistan.

The admission, from General Mark Milley, Chairman of the Joint Chiefs of Staff, was one of a number of significant revelations in a lengthy session with the Senate Armed Services Committee on Capitol Hill.

The general was joined by the head of US Central Command, General Frank McKenzie, and Secretary of Defence Lloyd Austin for a day of intense questioning from both Republican and Democratic lawmakers.

Among the revelations it emerged that:

• America’s top military commanders had recommended to President Biden that he should maintain at least 2,500 troops in Afghanistan, a recommendation the president had claimed had not been given.
• The military commanders had been taken by complete surprise at the speed with which the Afghan military collapsed.
• The ability of America to defend against a terror threat from Afghanistan is diminished.

In separate comments in the same hearing, General Milley also revealed remarkable details of conversations he’d had with his Chinese counterpart about a Chinese concern that former president Donald Trump planned to attack.

On Afghanistan, General Milley was asked if he thought the chaotic withdrawal last month had damaged America’s credibility.

The general said: “I think that our credibility with allies and partners around the world, and with adversaries, is being intensely reviewed by them to see which way this is going to go, and I think that damage is one word that could be used.”

His boss, Secretary of Defence Lloyd Austin, also giving evidence, disagreed.

“I think our credibility remained solid…” Secretary Austin, a former general, said. “Clearly there will be people who question things going forward.”

A central theme of the questioning was the degree to which the generals had warned the president of the consequences of a complete military withdrawal.

Centcom (U.S. Central Command) commander General McKenzie said that he recommended America maintain 2,500 troops in Afghanistan, a recommendation which General Milley said he agreed with.

The testimony appears to contradict President Biden’s claim to the contrary during an interview last month.

“I also had a view that the withdrawal of those forces would lead inevitably to the collapse of the Afghan military forces, and eventually the Afghan government,” General McKenzie said.

“I stated consistently that my position was, if you go below 2500 you’re going to look at a collapse of the Afghan military, I didn’t foresee it to be days… I thought it would take months.”

General Milley said: “In the fall of 2020, my analysis was that an accelerated withdrawal without meeting specific and necessary conditions risks losing the substantial gains made in Afghanistan, damaging US worldwide credibility, and could precipitate a general collapse of the Afghan government, resulting in a complete Taliban takeover or general civil war.”

He added: “That was a year ago, my assessment remained consistent throughout.”

Republican lawmakers reacted with anger against the president, a position summed up with remarks by Republican Senator Ben Sasse, who said: “President Biden lied when he told the American people that nobody urged him to keep 2,500 troops in Afghanistan.

“Today, under oath, General McKenzie flatly contradicted the president. This is the worst American foreign policy disaster in a generation and the president is trying to cover his ass with political spin.”

In one of the few interviews President Biden gave last month defending his Afghan policy, he told George Stephanopoulos of ABC News that military advisers had not warned him against bringing home troops or that at least 2500 were needed to prevent a Taliban takeover.

“No one said that to me that I can recall,” he told Stephanopoulos.

On the collapse of the Afghan armed forces, who had been trained for years by the American and other NATO forces to have the capability to stand alone, the generals were frank in their admissions.

“The fact that the Afghan army we and our partners trained simply melted away – in many cases without firing a shot – took us all by surprise,” Mr Austin said. “It would be dishonest to claim otherwise.”

“In the end we couldn’t provide them with the will to win,” Mr Austin conceded.

The chaos which unfolded at the airport in Kabul as tens of thousands of Afghans and other foreign nationals tried to escape the Taliban takeover eventually resulted in the deaths of 13 US troops and a mistaken US airstrike which killed 10 Afghans including 7 children.

The US military was attempting to target Islamic State militants.

In separate comments, General Milley was asked about conversations he’d had with his Chinese counterpart in the last days of the Trump presidency.

It emerged in recently published books on that presidency that General Milley had spoken to Chinese General Li Zoucheng twice in October 2020 and on 8 January 2021, just two days after Trump loyalists stormed the Capitol.

It had been suggested that General Milley had acted inappropriately in making the calls and that he was undermining the commander-in-chief, President Trump.

But in evidence, the general defended himself, saying his duties were to “deconflict military actions, manage crisis and prevent war between great powers armed with nuclear weapons”.

“I personally informed both Secretary of State Pompeo and White House Chief of Staff Meadows about the call, among other topics.”

Without providing classified details, the general revealed that US officials had picked up intelligence that the Chinese were concerned that America was preparing an attack on China.

He said the calls, part of a standard line of communication with his Chinese counterpart, were intended to reassure China that the US was not planning an attack.

He told the committee that he was “certain” that President Trump “did not intend on attacking the Chinese, and it is my directed responsibility to convey presidential orders and intent”.

He also referenced a conversation he’d had with Speaker Nancy Pelosi in which she had inquired “about the president’s ability to launch nuclear weapons”.

General Milley said: “I sought to assure her that nuclear launch is governed by a very specific and deliberate process… There are processes, protocols and procedures in place and I repeatedly assured her there is no chance of an illegal, unauthorised or accidental launch.”

He added that he was “not qualified to determine the mental health of the President of the United States”.