A woman has been appointed by the leader of the Islamic State group, Abu Bakr al-Baghdadi, to lead a new all-female battalion in Syria,the al-Arabiya news site quoted an activist as saying on Sunday.

Nada al-Qahtani who joined the group after leaving Saudi Arabia in 2013 is said to have lead the all-female modesty police, al-Khansaa Brigade in the group's de-facto capital of Raqqa in Syria. Another leader of the group is believed to be Britain Aqsa Mahmood who disappeared from her home in Glasgow in November 2014, and flew to Syria to marry an IS fighter.

According to al-Arabiya, al-Qahtani, who along with Mahmood led an estimated 800 girls in the brigade will now supposedly lead a new branch of the brigade in the Syrian province of Hasakeh after meeting with Baghdadi twice.

The female fighter “is now present in Hasakah… and she plays a prominent role on the level of communicating with foreign fighters,” al-Arabiya quoted the activist as saying.

While the all-female IS battalion led by al-Qahtani is a new step for the group, it is not the be the first all-female fighting in Syria. In December, i24news reported on an all-female Christian female militia battling IS in Hasakeh who following in the footsteps of Syria's other main female force battling the jihadists -- the women of the YPJ, the female counterpart to the Kurdish People's Protection Units or YPG.

Meanwhile, aid groups hope to use the lull in fighting that has claimed 270,000 lives and displaced more than half the population to deliver desperately-needed supplies.

United Nations Resident Coordinator in Damascus Yacoub El Hillo said in a statement on Sunday that the UN and other aid organizations hope to use the ceasefire to deliver aid to an estimated 154,000 Syrians in besieged areas in the next five days.

"It is the best opportunity that the Syrian people have had over the last five years for lasting peace and stability," he added.

The UN estimates there are close to 500,000 people living under siege and another 4.6 million who are in need of aid who live hard to reach areas.

Read more: Under the veil in Raqqa