KABUL - Afghanistan will release 88 prisoners as planned even though the United States considers them dangerous and wants them to remain in detention, the board reviewing their cases told Reuters.The prisoners are being held at a jail at the Bagram air base north of Kabul. The United States only recently transferred the prison to Afghan control after it had become a serious source of tension with the Afghan government.President Hamid Karzai instructed Afghan intelligence officials to provide the review board with more evidence against the prisoners, after the United States said there was proof of their involvement in the killing of foreign troops and they posed a serious threat to security.But the head of the review board, Abdul Shakor Dadras, said the evidence did not warrant keeping the prisoners any longer. “The documents we have seen so far provide no reason to convict them,” Dadras told Reuters by telephone late on Sunday. “Our decision is to release them as soon as possible if there is no incriminating evidence against them.”The disagreement over the prisoners is a further strain on Afghan-US relations already seriously soured by Karzai’s refusal to sign a bilateral security deal to shape the US military presence after most foreign troops leave this year.US senators in Afghanistan last week pressed the president to stop the release, warning it would irreparably damage relations with the United States.The planned release has also alarmed many senior Afghan security officials, who often see released prisoners return to the battlefield.US officials say about 40 percent of the prisoners were involved in attacks in which 57 Afghan civilians and members of the Afghan security forces were killed or wounded. Thirty percent of the prisoners had taken part in direct attacks that killed or wounded 60 members of Afghanistan’s US-led NATO force. Karzai’s office did not immediately comment. Meanwhile, former British defence chiefs warned Monday that parts of southern Afghanistan could fall to the Taliban when British troops leave this year, despite Prime Minister David Cameron recently saying they had accomplished their mission.Former commander of the elite Special Air Service Richard Williams told the Times that there was already evidence of growing collaboration between Taliban insurgents and Afghan soldiers and politicians in the Helmand Province.“I will be very surprised if the future governor of Helmand...is not very closely connected to those who we call the Taliban,” he told the paper. “We will end up in a very uncomfortable position, where people will say: ‘We’ve lost nearly 500 guys, most of those were in Helmand, and at the end of it all, we have handed Helmand back to a Taliban-sympathetic governor.”Cameron faced criticism last month for saying that NATO-led foreign troops had accomplished their mission of providing security in Afghanistan, in an echo of former US president George W. Bush’s much-derided comments on Iraq in 2003.Britain currently has around 5,200 troops in Afghanistan, down from 9,000 at the start of 2013, and plans to have no combat troops on the ground by the end of this year.David Richards, who was chief of the defence staff until last year, doubted the Afghan army could cope once the drawdown was complete, saying the ability to deal with insurgents would “rapidly fall away”. “More importantly, the signal of a loss of confidence in Afghanistan would have a devastating effect on the Afghan economy and, therefore in turn, lead to a breeding ground for militant jihadists to return,” he told the Times.