WASHINGTON - Former US Attorney General Ramsey Clark on Friday visited Fort Worth, Texas, to show support for Aafia Siddiqui, a Pakistani neuroscientist, who is incarcerated at Federal Medical Center Carswell, according to a media report.

Clark, attorney general from 1966 to 1969, was joined by a number of other supporters of Dr Siddiqui in Burnett Park outside the federal courthouse in downtown Fort Worth, The Star-Telegram reported.

Clark, 85, was quoted as saying in the newspaper that US authorities have never said why they suspected Dr Siddiqui of working with Al-Qaeda. "No one has ever explained why she was arrested in the first place," Clark said. "It's unbelievable what's happening to her." Dr Siddiqui's supporters plan to observe the 10th anniversary of her arrest in 2003 by gathering outside Naval Air Station Fort Worth, the military base near the prison.

She resurfaced in 2008 in Ghazni, Afghanistan, but was arrested again. Authorities claim she was carrying bomb-making materials and recipes.

While in custody, she was accused of grabbing the gun of a US interrogator and trying to shoot servicemen - an allegation she categorically denied. She was shot twice and recovered, then was convicted in February 2010 of attempted murder and assault.