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He said in a Facebook message that he had escaped to avoid a “flood of bloodshed” in clashes with the Taliban.
But US officials have grown increasingly critical of Mr Ghani over his sudden exit, saying it accelerated the collapse of his US-backed government and security forces.
“You had the government of Afghanistan, the leader of that government, get in a plane and taking off and going to another country,” US President Joe Biden said last week when asked why things had gone so wrong in Afghanistan.
This week, two Republican congressmen on the House Committee on Oversight and Reform wrote to Secretary of State Antony Blinken and Attorney General Merrick Garland asking for further information on an allegation made by Afghanistan’s ambassador to Tajikistan that Mr Ghani had stolen $169 million from state funds.
“Not only did President Ghani flee the country of Afghanistan prematurely and contribute to the rapid fall of the American-backed democratic government in Kabul, but he brought with him duffel bags full of cash,” the two members of Congress, James Comer and Glenn Grothman, asserted in their letter, first published by Fox News.
Mr Ghani has strongly denied any allegations of wrongdoing.
In a recorded statement aired after his arrival in the UAE last week, he said his security team had forced him to leave Kabul and added that he took only one set of clothes with him, leaving all else behind.
The two Republicans wrote that if Mr Ghani, who once wrote a book entitled Fixing Failed States and is a former World Bank economist, had “diverted funds from their intended purposes, the US should bring him to justice".
US officials are also upset with Mr Ghani for reneging on a last-minute deal with the Taliban, a source with immediate knowledge of the discussions said.
Under the agreement made in the hours before the Taliban seized Kabul, Mr Ghani said he would resign and grant the Taliban an official two-week handover period — but he fled Afghanistan before the plan could ever be enacted.
The Afghan president had recorded a message announcing his resignation, the source said.
Upon its release, the Taliban agreed they would not attack the capital for two weeks while the Pentagon flew US citizens, troops and Afghan allies out, and while the formal transition of power was hammered out at a loya jirga meeting of senior Afghan officials, the source added.
One of Mr Ghani's close aides declined repeated requests to comment on this story. A second close aide did not respond to requests for comment.
The deal was agreed to over a 24-hour period from August 13-14, the source said. But Mr Ghani never released the recording of his resignation and left Afghanistan even before the Taliban had entered Kabul in large numbers. He did not leave a plan in place for what should happen next, the source added.
In an April letter verified by The National, Mr Blinken wrote to Mr Ghani asking him to help accelerate peace talks that were going on at the time and warning him of the Taliban’s strength.
“I am concerned that the security situation will worsen and that the Taliban could make territorial gains,” Mr Blinken wrote.