If the US forces are not cut off from ISIS they no longer have an excuse to continue occupying this part of Syria. (Or will they insist they get to leapfrog over the Syrian army?)
Russians are saying it will be them and the Syrians — rather than the Americans — who will be advancing along the Iraqi border towards al-Bukamal (the major border crossing in the Euphrates valley coveted by the Pentagon):
“The coalition air forces and the strongholds of the forces of New Syrian Army have blocked the way of the government forces, tasked with defeating IS groups.”
“This is a violation of the sovereign right of Syria to protect it borders.”
There is a video of the Russian briefing, but so far not yet translated (except for an incomplete summary at RT).
UPDATE — Apparently in sync with the Syrian army move south, Iraqi forces likewise advanced against ISIS from their side and met on the border. Thus Syria has not just reached the formal Iraqi border, but actually re-established an actual link to Iraq: