Money used to pay a ransom for an Afghan diplomat reached al-Qaida in 2010, according to Afghan and Western officials, but CIA declined comment

About $1m provided by the CIA to a secret Afghan government fund ended up in the hands of al-Qaida in 2010 when it was used to pay a ransom for an Afghan diplomat, the New York Times reported on Saturday.

Al-Qaida leader Osama bin Laden had at first been concerned about the payment, fearing the CIA knew about the money and had tainted it with poison, radiation or a tracking device, the Times said, and suggested it be converted to another currency.

The newspaper said letters about the ransom payment were found in the 2011 raid by US navy Seals, who killed bin Laden at his compound in Abbottabad, Pakistan. The communications were submitted as evidence in the trial of Abid Naseer, who was convicted this month in New York of supporting terrorism and plotting to bomb a shopping center in Manchester, England.

The Times said Abdul Khaliq Farahi was the Afghan consul general in Peshawar, Pakistan, when he was kidnapped in 2008 and handed over to al-Qaida. He was released two years later after Afghanistan paid al-Qaida $5m, a fifth of which was CIA money that came from an Afghan government fund that received monthly cash deliveries from the agency, the Times said.

The newspaper said an al-Qaida member wrote bin Laden that the ransom money would be used for weapons, operational needs and payments to families of al-Qaida fighters held in Afghanistan.

The Times said the cash the CIA delivered to the Afghan presidential palace under President Hamid Karzai was used to buy the support of warlords, legislators and others, as well as to cover expenses for clandestine diplomatic trips and housing for senior officials. Afghan officials told the newspaper the payments have slowed since Ashraf Ghani became president in September.

In addition to the al-Qaida correspondence, the Times story was based on conversations with Afghan and Western officials, the newspaper said, noting that the CIA declined to comment.