Sources on the ground in Syria are reporting a massive explosion at what appeared to be an ammunition depot at the Syrian Army Abu Dhuhour Airbase.
That base is near Idlib in the North of Syria, and CONFLICTING REPORTS mention a possible Israeli air strike, but those reports are NOT CONFIRMED. It is well known that numerous Russian troops occupy that base.
This is a developing story, check back for updates.
UPDATE 11:50 AM EDT --
Reports now saying explosion was Israeli airstrike against Iranian weapon storage facilities at the air base.
"Our stance against Israel is the same stance we have always taken. #Israel is a malignant cancerous tumor in the West Asian region that has to be removed and eradicated: it is possible and it will happen. "