Islamic State captures northern Syrian town leading to Turkish border

ALEPPO, Syria, May 31 (UPI) -- Islamic State rebels made further gains against rival rebel groups and the Syrian government Sunday, capturing towns north of Aleppo on roads leading to Turkey.

IS fighters seized the towns of Soran A'zaz, al-Bel and al-Hasila, the Syrian Observatory for Human Rights reports.

Soran A'zaz lies six miles south of the city of A'zaz, which itself is just south of the Bab al-Salama border crossing into Turkey.

At least 31 rebel fighters and 22 IS militants died in the fighting, according to SOHR.

Along with the regime of Syrian President Bashar al-Assad, IS forces are rivals to other Islamist rebel factions in the country, including al-Qaida's Nusra Front, though the groups have occasionally aligned against regime forces or against moderate rebel clans.

Amid the weekend fighting, the Syrian government continued bombing rebel-held areas in Aleppo province. On Saturday 72 people, mostly civilians, were killed in barrel bomb attacks on the city of Aleppo and the IS-held village of al-Bab.

Earlier in May human rights group Amnesty International released a report characterizing the Syrian military's barrel bombing of Aleppo -- which between January 2014 and March 2015 killed 3,124 civilians and 35 rebel fighters -- as "crimes against humanity."

IS forces in recent weeks have captured the central Syrian city of Palmyra and the last government-controlled border crossing between Syria and Iraq. IS fighters also sent Iraqi troops fleeing from the city of Ramadi, Iraq, earlier this month.

Forces loyal to Bashar al-Assad have been pushed into Syria's western provinces by a series of rebel advances, including an April assault by allied Islamist factions that saw the Syrian military lose its last major urban stronghold in Idlib province.