Pres. Putin. Pres. Rouhani and Pres. Erdogan will launch phase 2 after 4 april 2018. They all want the US out of Syria, period. Multiple operations against US forces and their YPG slave puppets are about to begin especially in Aleppo governorate and Deir ezzor governorate.
the US already knows this & has been amassing troops near alOmar oil field, 10 kms north of AlMayadin, also protecting ISIS fighters there who will spearhead an attack against Syr/Rus forces. The US has also been fortifying its positions in Manbij, fearing an imminent Turk attack
Iran on its turn ordered hundreds upon hundreds of Hashd al Shaabi to get battle ready & to counter any US/ISIS terrorist Op. against Syr/Rus forces from Iraqi soil. While Iraqi PM alAbadi is preparing the Iraqi Army to back Hashd & to defend Iraqi borders from any ISIS inursion