The Taliban will be denied access to any Afghan reserves held in US accounts, a US administration official told AFP on Monday.

As US forces were evacuating Afghanistan's capital after the Taliban's swift takeover, the official said: "Any Central Bank assets the Afghan government have in the United States will not be made available to the Taliban."

The central bank's gross reserves totaled $9.4 billion at the end of April, according to the IMF.

But most of those funds are held outside of Afghanistan, according to a person familiar with the matter. It was not immediately clear what share of the assets are held in the United States.

The Taliban's seizure of power comes after NATO withdrew its 9,500-strong mission on the back of a decision from US President Joe Biden to pull out his troops.

Afghan president Ashraf Ghani flew out of the country on Sunday night as the insurgents encircled the capital, capping a military victory that saw them capture all cities in just 10 days.

The country's central bank governor Ajmal Ahmady went to Twitter to detail his harrowing escape from the country on a military plane on Sunday, after he and his team tried to stabilize the currency amid the Taliban advance towards the capital.

Ahmady, who did not say where he was, said the central bank was informed on Friday that "given the deteriorating environment, we wouldn't get any more dollar shipments," and he met Saturday with banks and money exchangers to reassure them.

"Once (the) president's departure was announced, I knew within minutes chaos would follow. I cannot forgive him for creating that without a transition plan," he tweeted Monday.

"It did not have to end this way. I am disgusted by the lack of any planning by Afghan leadership. Saw at airport them leave without informing others."

Taliban fighters patrol the streets of Kabul, after a stunningly swift end to Afghanistan's 20-year war
Along with the fall of Kabul into the hands of the Taliban is the lingering question of what will happen to Afghanistan's massive rare earths industry that remains largely untapped. AFP / -

In addition to freezing assets, Washington could also block aid to Afghanistan from multilateral lenders like the International Monetary Fund and World Bank, as it has with other regimes it does not recognize, like Venezuela.

"Afghanistan is tremendously dependent on foreign aid... so access to international economic funds will be crucial," said Vanda Felbab-Brown, a foreign policy expert at The Brookings Institution.

But cutting off funds in an attempt to undermine a Taliban government "has massive humanitarian consequences, and human and economic development consequences," she told AFP.

And there are political calculations as well since other sources of financing like Russia, China and Saudi Arabia will not have the same focus on women's rights or human rights as Washington, and may simply focus on extracting an anti-terrorism pledge, she said.

The IMF in June released the latest installment of a $370 million loan to Afghanistan approved in November to help support the economy amid the Covid-19 pandemic.

At the time, the fund said the government had kept its economic program on track despite the fact "security has deteriorated and uncertainty has risen as the peace talks between the government and Taliban stalled, with the US and NATO troops set to withdraw by September."

The World Bank meanwhile has more than two dozen development projects ongoing in the country and has provided $5.3 billion since 2002, mostly in grants.

The United States provide $4.7 billion in aid in the 2019 fiscal year alone, according to government data.

"The Taliban government members have no experience as to how to deal with international donors," Felbab-Brown said.

"They don't have any experience with administering large international aid packages."

Coronavirus