Former Guantanamo Bay detainee Moazzam Begg appeared in court in London on Saturday charged with providing terrorist training and funding terrorism in Syria.
The 45-year-old from Birmingham in central England indicated he would plead not guilty to the charges and was remanded in custody until the next hearing on March 14.
Begg, who was arrested on Tuesday at his home, spent three years at the US detention camp at Guantanamo Bay on Cuba before being released without charge in 2005.
He has since become an outspoken critic of the so-called "war on terror" and is outreach director of Cage, a British group which campaigns for detainees' rights.
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Begg appeared at Westminster Magistrates Court alongside a 44-year-old woman, Gerrie Tahari, also of Birmingham, who is charged with facilitating terrorism overseas.
Tahari, who was also arrested on Tuesday, denied the charge and was remanded in custody until March 14.
Two men arrested on the same day, aged 20 and 36, remain in police custody on suspicion of facilitating terrorism overseas, West Midlands Police said.
Begg moved to Afghanistan with his wife and three children in 2001 but fled to Pakistan after the US-led invasion to topple the Taliban after the September 11 attacks.
He was detained in Islamabad as an "enemy combatant" in February 2002 and taken to the Bagram prison in Afghanistan and then Guantanamo.