The State Department said on Wednesday that the US welcomed Tunisia's decision to free or grant conditional parole to more than 1600 prisoners.
Adam Ereli, the State Department's deputy spokesman, said some had been described by human rights groups, non-governmental organisations (NGOs) and independent observers as political prisoners.
"It is regrettable that the State Department seems to give credit to claims by some NGOs that do not know about the political life of the country and its realities," Tunisia's government said in a statement on Thursday.
"There are no political prisoners or prisoner of conscience" in Tunisia, the statement said, adding that those released were prisoners who had been tried and convicted in court of crimes, terrorist acts or plotting terrorism.
Ereli said the US regretted Tunisia's decision to ban a peaceful demonstration on 24 February by legal opposition parties and other moves limiting the ability of those parties to express their views.
Tunis insisted the demonstration had been planned "by illegal groups that have no judicial status, which is banned under Tunisian law".
Rights groups accuse officials of
a range of abuses
"Legally created political parties are free to carry out their activities in Tunisia, on the lone condition of respecting the public order of course," the Tunisian government statement said.
The pardons by Zine El Abidine Ben Ali, Tunisia's president, were announced on Saturday and came in advance of the North African nation's 50th anniversary of independence from France.
Human-rights groups have long criticised Tunisia for a range of buses, from muzzling the press to putting hundreds of political prisoners behind bars and labelling them common criminals.