Ankara, Jun 30 (IANS/EFE): At least 20 members of families living under Islamic State crossed from Syria into Turkey amidst the Kurdish advance on al-Raqqa, the main stronghold of the radical group, the Syrian Observatory for Human Rights (SOHR) said on Monday.

The London-based NGO noted that the family members "included 13 women, one of them is a Tunisian doctor," and that initial reports showed that five of those who fled across the border were arrested by Turkish authorities.

The relatives of IS militants entered the Turkish border from al-Raii area, in the northern Syrian province of Aleppo, SOHR added.

Two weeks ago, the NGO said that the radical organisation relocated foreign fighters' families from al-Raqqa to safer areas under its control in northeastern Aleppo.

Clashes between IS and Kurdish People's Protection Units have been on the outskirts of al-Raqqa.

Meanwhile, activists inside al-Raqqa observed a remarkable reduction in Islamic police patrols and the near total disappearance of its female members.