The three Afghan journalists were detained over the past week - Rahmatullah Naikzad and Mohammad Nadir by the NATO-led coalition and Afghan security forces, and the third by the Afghan intelligence service.
NATO said all three had been released by Friday evening.
Naikzad, who has worked for Al-Jazeera and as a freelancer for The Associated Press, was detained by coalition forces in the eastern town of Ghazni. He was released Friday and has returned home, he told the AP. Earlier in the day, Al-Jazeera cameraman Nadir, who was arrested Wednesday in the southern city of Kandahar, was also released.
"After reviewing the initial intelligence and information received during questioning, the two men were not considered a significant security threat and were released," said Rear Adm. Gregory Smith. "During their brief detention, they were treated humanely and in accordance with international law and U.S. policies."
Naikzad said that during his custody he was sad and very uncomfortable and kept recalling the early morning raid on his home.
"Now I'm very, very happy," he said by telephone from his home. "I can see my wife, my children, my mother, my family. I'm so, so glad. It is a gift God has given me."
He said he was not mistreated, but his eyes were covered and his hands were bound. He said he was not given proper time for prayer.
NATO had said it had information linking the men to networks that act as a mouthpiece for the Taliban and spread insurgent propaganda.
The third journalist, Hojatullah Mujadadi, a radio station manager in Kapisa province north of Kabul, was arrested by Afghan agents on Saturday. NATO said in a statement that he had been freed by Afghan authorities as well, but did not provide further details. Afghan officials could not immediately confirm that information.
The arrests sparked an angry reaction from Afghan media workers, journalism advocates and human rights groups. Karzai called Thursday for their quick release.
NATO has defended the detentions, but the alliance's secretary-general on Thursday said he was open to their release if they were found innocent.