An alleged Islamic State affiliate is going on the offensive against Jabhat a-Nusra and Ahrar a-Sham’s positions from its stronghold in the southwest corner of Daraa province where they control a smattering of villages sandwiched between the Israeli and Jordanian borders.

Liwa Shuhadaa al-Yarmouk (LSY) advanced about six kilometers outside the pocket they control where Nusra and Ahrar a-Sham have encircled them for more than a year. On Monday, LSY captured two towns from Nusra and Ahrar.

Why venture out of its corner now? Frankly, it’s not clear. But during Monday’s offensive, LSY fighters killed Nusra’s top military commander in Daraa, Abu Salah al-Musalama, reported pro-opposition Enab Baladi on Monday. Nusra confirmed its leader was killed, but did not comment further.

LSY was formed in 2012 in southwestern Daraa province as a branch of the Free Syrian Army, but in the years since has grown increasingly ideologically stringent and isolated from other rebel factions. It denies affiliation with the Islamic State, but looks and acts like a wannabe.

Since late 2014, LSY and Jabhat al-Nusra have battled for turf all the while picking each other off with tit-for-tat assassination operations.