US plans to withdraw all troops from Afghanistan by September 11

President Joe Biden will remove all US troops from Afghanistan before this year's 20th anniversary of the September 11 attacks, ending America's longest war around five months later than planned, a US official has said.

Biden has "reached the conclusion that the United States will complete its drawdown - will remove its forces from Afghanistan - before September 11," the official told reporters on condition of anonymity.

Biden will make an announcement on Wednesday that all US forces, in coordination with those of Western allies, will leave other than limited personnel to guard US diplomatic installations, the official said.

READ MORE: Can the US exit Afghanistan?

'Conditions-based approach'

Biden will not link the departure to conditions on the ground, where there are rising fears that the Taliban could make major gains against the internationally-backed government in Kabul.

"The president has judged that a conditions-based approach, which has been the approach of the past two decades, is a recipe for staying in Afghanistan forever," the official said, calling for a shifting of US priorities.

For Afghans the fighting will likely grind on. The official spoke shortly after US intelligence released a threat assessment report warning that the embattled Afghan government "will struggle" to hold off the "confident" Taliban if the US-led coalition withdraws.

Former president Donald Trump also favoured a withdrawal and reached a deal with the Taliban in February 2020 under which all US troops would leave by May 2021 in return for the insurgents' promise not to back Al Qaeda and other extremists – the original reason for the 2001 invasion.

READ MORE: A tale of two Talibans

'Forceful response'

The Biden official said that the withdrawal would begin in May and that the delay was largely logistic, with troops possibly out of Afghanistan well before September 11.

The official warned the Taliban of a "forceful response" if they strike US troops on the way out.

"We have communicated to the Taliban in no uncertain terms that is they do conduct attacks against US or allied forces as we carry out this drawdown," he said, "that we will hit back hard."

The threat assessment report published on Tuesday by the director of national intelligence said the Taliban "is confident it can achieve military victory."

"Afghan forces continue to secure major cities and other government strongholds, but they remain tied down in defensive missions and have struggled to hold recaptured territory or reestablish a presence in areas abandoned in 2020," it said.

READ MORE: Taliban warns against foreign troops staying beyond withdrawal deadline

Afghan peace talks in Istanbul

Turkey announced on Tuesday that a keenly awaited international conference on the Afghan peace process will be held in Istanbul from April 24 to May 4.

The high level and inclusive conference between representatives of the Afghan government and the Taliban is being co-convened by Turkey, Qatar, and the UN, according to a joint statement issued by the Turkish Foreign Ministry.

READ MORE: Turkey, US discuss Afghan peace process ahead of crucial Istanbul summit

“The co-conveners are committed to supporting a sovereign, independent and unified Afghanistan,” read the statement.

“The overriding objective of the Istanbul Conference on the Afghanistan Peace Process is to accelerate and complement the ongoing intra-Afghan negotiations in Doha on the achievement of a just and durable political settlement.”

The participants and agenda of the conference “have been the subject of extensive consultations with the Afghan parties,” according to the statement.

“The conference will focus on helping the negotiating parties reach a set of shared, foundational principles that reflect an agreed vision for a future Afghanistan, a roadmap to a future political settlement and an end to the conflict,” read the statement.

“It is our expectation that the conference will provide an important opportunity for all partners to reiterate support for the people of Afghanistan on their path toward inclusive peace, stability, and prosperity.”

READ MORE: Afghan leader proposes peace road map in three phases