Fierce clashes broke out in Damascus this week after rebel fighters infiltrated the city through tunnels, breaching the regime's security perimeter. The surprise offensive marked a rare advance after months of steady losses for rebel forces across Syria. The Iraqi Shi'ite militia Harakat Hezbollah al-Nujaba announced that it has joined pro-regime forces in the defense of Jobar and Abbasin districts, the outlying areas that came under attack. The militia is said to be effectively led by officers from the Iranian Revolutionary Guard Corps, against ponting  to Tehran's critical role in support of the Bashar Assad regime.

Meanwhile, the Qaeda-affiliated Hayat Tahrir al-Sham is said to have joined the rebel advance, launching opening attacks with suicide vehicle-borne improvised explosive devices (SVBIEDs). While having ostensibly broken from al-Qaeda, the ex-Nusra Front is emerging as a bridge between FSA-affiliated factions and the Qaedists. As the rebels become more desperate, sectarianism is becoming more dominant on both sides in the war.  (Long War Journal, LWJ, The Guardian)