He attributed the delay in handing over the rest to “technical issues,” but did not elaborate.
On Sunday, the U.S. also suspended the transfer of about 30 detainees that remained from the original group of about 3,000.
“Some 99 percent of the detainees captured before 9 March have already been transferred to Afghan authority, but we have paused the transfer of the remaining detainees until our concerns are met,” said Jamie Graybeal, a spokesman for the U.S.-led military coalition.
He said concerns focused on the Afghan government’s intentions to implement the March agreement, but would not explain further.
Afghan officials and analysts have said the dispute is over a system of administration detention that allows extended no-trial internment for wartime prisoners. Although this is permitted under the international laws on war, some Afghan officials say it may not be legal under the Afghan constitution.
“There are concerns on the U.S. side about division in the Afghan government over internment and that it is not constitutional,” said Rachel Reid, a senior policy adviser on Afghanistan for the Open Society Foundations. “The basic concern is that if they don’t have internment, they will be released.”
Another issue is how quickly Afghans arrested on the battlefield by U.S. forces are handed over to the government.
Foreign Ministry spokesman Janan Mosazai said all Afghan detainees have to be turned over within 72 hours. The U.S. wants to be able to keep detainees longer than that.
Associated Press Writers Amir Shah at Bagram Air Field and Deb Riechmann in Kabul contributed to this report.