Some detainees have already been taken by third countries
Afghan President Hamid Karzai has welcomed the decision by new US President Barack Obama to close the Guantanamo Bay prison.
He said it was a good decision that would help build international support for the fight against terrorism.
President Karzai has repeatedly called for all detained Afghan citizens to be released so that their cases can be dealt with at home.
Many prisoners in Guantanamo were captured in Afghanistan in 2001.
They were detained during the US-led war that drove the Taleban from power.
On Thursday, Mr Obama signed orders to close the prison camp "no later than one year from now" as well as all overseas CIA detention centres for terror suspects.
He also ordered a review of military trials for terror suspects and a ban on harsh interrogation methods.
"This decision by the United States is a major step toward bringing more international support to the struggle against terrorism and enlisting all nations in this war," President Karzai said in a statement.
Correspondents say that the detention facility has become a symbol of US injustice in much of the Muslim world.
Scores of Afghan citizens have passed through Guantanamo. As of October, 192 Afghans had been released from the facility, according to figures compiled by the US human rights group One World Research.
The BBC's Richard Lister in Washington says that calls for all inmates to be released will not happen for a number of reasons, not least because some are still perceived to present a genuine threat to the US.
The Pentagon said recently that 61 former Guantanamo prisoners had returned to fight the US and its allies in places like Iraq and Afghanistan.