(CNN) -- An anti-drone activist and journalist from Pakistan has been released, more than a week after he was abducted from his home in Rawalpindi.
Kareem Khan told reporters Friday how he was abducted by armed men who showed up at his family's home in the early hours of February 5, and then tortured him while he was in captivity.
Khan, from the tribal area of North Waziristan, lost his son and brother to a 2009 CIA drone strike, and had been set to travel to Europe to meet with parliamentarians when he disappeared, lawyer Shazad Akbar said in a news release.
He was also involved in legal proceedings against the Pakistani police concerning their failure to investigate the killing of his relatives.
At a news conference held only hours after he was freed, Khan told how between 18 and 20 armed men kidnapped him from his home.
"The men banged at our house door, broke the lock and barged in," he said. "They held guns to me and my family and told us to put our hands up. Took me to a car, handcuffed me, blindfolded me and drove off.
"My eyes still hurt from the tightness of the blindfold. My temples, eyes and forehead are all in pain because of how tight the blindfold was. My feet were constantly shackled and my feet were constantly handcuffed."
'Hung upside down'
Khan said he was not able to pinpoint where he was taken, nor who his abductors were. The scene of his torture was an underground room, he said.
"They abused me using vulgar expletives. Hung me upside down and sat on me while one other person beat my feet," he said.
He could hear other people while he was in the torture cell, he said.
Khan said his questioners "didn't mention drones, didn't mention my family. Only asked me about some names I couldn't recognize and what connection I had to them.
"I could not tell if my captors were from the intelligence agencies, they were from all ethnicities and did not give away anything that could identify them."
Khan said he had been told not to speak to the media but that he was unafraid.
"I brought my children to the city of Rawalpindi from Waziristan to provide safety to them but now we don't feel safe anywhere," he said.
"I am going to Europe to highlight how my people are being abused by drone strikes. Our brothers and children are peaceful citizens who are being targeted. We are not terrorists that are being killed."
Charity: Serious questions to answer
Reprieve, a UK-based charity that provides legal support to prisoners unable to pay for it themselves, said Khan intends still to go ahead with his trip to Europe this week. He was due to speak with German, Dutch and British parliamentarians about his personal experience of drone strikes.
Reprieve legal director Kat Craig said it was a "huge relief" that Khan had been freed, although his mistreatment was deeply concerning.
"No one should have to suffer as he and his family have done for simply trying to get to the truth about the deaths of their loved ones," she said. "Serious questions remain for the Pakistani government on how this was allowed to happen."
Khan spoke to CNN in December 2010 about the airstrike a year earlier that had targeted his home in Machikhel, a village in North Waziristan.
Khan said the missiles killed his 35-year-old brother, a teacher with a master's degree in English literature; his 18-year-old son, and several others.
He filed a $500 million lawsuit against the U.S. government.
CNN's Chandrika Narayan and Saleem Mehsud contributed to this report.