The Islamic State has demanded $6.6 million for the release of a 26-year-old American woman abducted last year while on a humanitarian mission in Aleppo, Syria, ABC reported Tuesday. The woman is among the known Americans taken hostage by the Islamic terrorist group, along with journalists Steve Sotloff and James Foley, who was seen beheaded in a video posted on YouTube last week. The woman's family has asked that her name not be released.

Besides demanding a ransom for the U.S. woman, the Islamic State, also known as ISIS, asked for the release of Aafia Siddiqui, a Pakistani woman convicted in the U.S. of the attempted murder of a U.S. soldier in Afghanistan. American officials said that she has also worked with al Qaeda, the terrorist group behind the 9/11 attacks. But speaking via the Peace Through Justice Foundation, Siddiqui's family criticized the Islamic State's ransom demand and the group's use of their daughter's name when it publicly demanded the $6.6 million payment.

"While we deeply appreciate the sincere feelings of those who, like us, wish to see the freedom of our beloved Aafia, we cannot agree with a ‘by any means necessary’ approach to Aafia’s freedom," the family said in a letter. "Nor can we accept that someone else’s daughter or sister suffer like Aafia is suffering."

Islamic State militants claimed Foley's videotaped beheading was in retaliation for American airstrikes that began Aug. 8 against the radical group in Iraq. The end of Foley's execution video shows Sotloff, who was abducted in August 2013, and a threat is made that he will be killed if the U.S. does not call off its airstrikes.

Another American journalist, Peter Theo Curtis, was released by al Qaida's Syria affiliate, al-Nusra, on Sunday. The details of his release have not been made public.