The men had returned to Pakistan nine months ago, after detention at the US facility, Tahir Ashrafi, a religious affairs adviser for the government in the eastern Punjab province said on Monday.
"These are people who have been declared innocent by America. Our agencies have thoroughly interrogated them," Ashrafi said outside the Kot Lakhpat jail.
"They have not been found to be involved in any kind of terrorist activity."
He said the men had "furnished surety bonds that they will maintain good behaviour and will not be involved in any anti-state activities".
Hundreds of Pakistanis had gone to Afghanistan to fight alongside the Taliban against the United States. After the US military operation ousted the Taliban from power in late 2001, many Pakistanis were jailed in Afghanistan, and some were sent to Guantanamo. Since September 2004, 35 Pakistanis have been released from the prison.
"They have not been found to be involved in any kind of terrorist activity"
Pakistan's provincial minister
Pakistan was a Taliban ally before it switched sides to back the United States in the "war against terrorism" following the September 11 attacks.
Pakistan security forces have captured more than 700 people they say are al-Qaida suspects, including several senior figures.
However, President General Pervez Musharraf's decision to back the United States angered radical Islamic groups that have been blamed for subsequent attacks in Pakistan.