KANDAHAR, Afghanistan (Reuters) - The prisoner swop that freed the last United States prisoner of war in Afghanistan shows the Taleban have legitimacy as a movement capable of negotiating successful deals with the United States, a Taleban commander told Reuters on Thursday.

Five Taleban prisoners including senior members of the ousted regime were released from Guantanamo Bay, Cuba in exchange for 28-year-old Sergeant Bowe Bergdahl, who had been kidnapped by the Taleban.

"This gives the Islamic Emirates more legitimacy in front of the world. It shows we are able to deal directly with the Americans and also successfully," Mr Maulvi Mubarak, shadow Taleban chief of the Shah Wali Kot district in Kandahar, said.

Mr Mubarak said the deal would also boost morale among the Taleban's ranks, including the hundreds of men under his command in three neighbouring districts. "This will give us more courage and determination to carry on this holy task," he told Reuters.

The Taleban government was overthrown by a US-led coalition in 2001 after the Sept 11, 2001 attacks but the insurgency still has its own shadow governors across the country.

Despite over 13 years of war and billions spent on reconstruction, the insurgency remains a powerful force and has gained ground as foreign troops have withdrawn, with most due to leave by the end of 2014.

Bergdahl was handed over to U.S. special operations forces in Afghanistan on Saturday after five years in captivity in exchange for the transfer to Qatar of five Taleban members.

It provoked criticism from some lawmakers in Congress who were angry that US President Barack Obama's administration had not alerted them in advance, while some of Sgt Bergdahl's former comrades have said that he was captured after deserting.