Neither the International Red Cross nor Afghan government officials have confirmed the claim.
One of the Taliban spokesman quoted, Qari Yusof Ahmadi, said the Taliban's leadership council decided to release the two women "unconditionally" and as a "gesture of goodwill."
The militants reportedly have insisted the release of Taliban prisoners remains a condition of the release of the other hostages.
Earlier today, Taliban negotiators claimed talks with South Korean diplomats were going well and that the militants expected to reach an agreement securing the release of the 21 hostages.
The captors in July killed two of the initial group of 23 captives, both of them men.
The hostages are volunteers for a Christian aid effort to bring relief and medical care to beleaguered residents of southern Afghanistan. They were all abducted from a bus traveling on the Kabul-to-Kandahar highway.
The Afghan government has repeatedly said it is unwilling to exchange Taliban prisoners for the hostages, which has been among the reported demands of the kidnappers.
(compiled from agency reports)