On December 13, a joint US-Syrian patrol was ambushed by a member of Syria’s own security forces near Palmyra, a city in central Syria once controlled by the ISIL (ISIS) group.Two US soldiers and an interpreter were shot dead, and four people were wounded, before Syrian forces killed the gunman.Recommended Stories list of 3 itemsend of listIn the aftermath of the attack, US and Syrian officials linked the attacker to ISIL, which once controlled vast swaths of Syria and Iraq, and promised to retaliate.The incident highlights the growing cooperation between the United States and Syria against ISIL, particularly after Damascus joined the US-backed coalition against the group in November.While it is still unclear if the attacker was a member of ISIL or another group opposed to US-Syrian relations, analysts say that cooperation between the two countries is strong and growing stronger.“The Syrian government is responding very robustly to fighting ISIL following US requests to do so, and it is worth noting that HTS [Hayat Tahrir al-Sham], before it was in government, had a long-term policy of fighting ISIL,” Rob Geist Pinfold, a scholar of international security at King’s College London, told Al Jazeera, referring to Syrian President Ahmed al-Sharaa’s former group.“It [HTS] did it in Idlib, and cracked down on insurgents and cells, and this is more a continuation of that policy.”Syria’s Minister of Interior spokesman, Noureddine al-Baba, told Syria’s Al-Ikhbariah TV that there was no direct chain of command to the gunman within Syria’s internal security forces, and that …