The Taliban commander responsible for increasingly sophisticated bomb attacks on British soldiers in Afghanistan is a former detainee of Guantanamo Bay released from prison in Kabul last year by Hamid Karzai’s government, The Times learned.

Abdullah Ghulam Rasoul was held in Guantanamo for six years before being released to Afghan authorities in December 2007, after a U.S. military review board decided unanimously that he was no longer a threat.

British and Taleban officials have told The Times that Rasoul has since resurfaced as Mullah Abdullah Zakir, the Taliban’s new operations chief in Helmand and the architect of a new offensive against British troops.

Since he took over, the “asymmetric” threat from the Taliban has risen dramatically, with greater numbers of more sophisticated and powerful roadside bombs used against British troops. “He is a serious player,” one Whitehall official said.

Although Rasoul was released from Guantanamo after convincing interrogators that he had never held military command, Taliban officials told The Times that he had been a high-ranking commander close to the Taliban’s supreme leader, Mullah Omar.

The disclosure will further complicate President Obama’s efforts to persuade countries to take in Guantanamo detainees and allow him to close the camp within a year as promised.

Rasoul, known as Detainee 008 in Guantanamo, is the latest in a line of former inmates and released Taleban prisoners to return to the fight in Afghanistan, including Maulavi Ghulam Dastagir, who was released on the personal orders of President Karzai.

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