The Afghan government said Monday it would not release the last 320 Taliban prisoners it is holding until the insurgents free more captured soldiers, defying a traditional council held last week and further delaying intra-Afghan talks sought by the United States.  The talks, which were laid out in a peace deal signed between the United States and the Taliban in February, were expected to begin on Thursday but are now postponed indefinitely. Suhail Shaheen, the Taliban’s political spokesman, said the group had fulfilled its obligations and was not aware of any other security personnel in its custody who were to be released. “We have released 1,000 prisoners that we had promised to release,” Shaheen said. The Taliban have said they are ready to open talks with the government within one week of the release of the last Taliban prisoners.