1. Iran's priorities in Syria and Iraq can best be tracked by following the movements of one of its highest-ranking military leaders, Maj. Gen. Qassem Soleimani. In September 2016, the commander of the Islamic Revolutionary Guard Corps' (IRGC's) elite Quds Force made an appearance south of Aleppo just before loyalist forces launched the final offensive that led to the critical city's capture. Seven months later, he was spotted in the northern Syrian governorate of Hama as loyalist troops, backed by Iran, geared up for a difficult fight with rebel forces on the outskirts of the provincial capital.
2. Soleimani is currently on the move once again. On June 12 the elusive figure paid a visit to Iranian-led militia units on the border between Syria and Iraq, giving prayers of thanks for their recent victories in the area. His presence is telling of the newest phase unfolding in Syria's protracted civil war: the race to the Syria-Iraq border.
3.With the ISIS being slowly being driven out of Syria and death of Baghdadi stated to be most probable by Russia, its enemies are scrabbling to pick up the territory it leaves behind. Syrian rebels, supported by the U.S.-led coalition, are facing off against the government of President Bashar al Assad, backed by Iran and Russia, to wrest control of the extremist group's remaining positions from its weakened grasp. Yet despite having the same finish line in sight, each participant is driven by its own interests, and is willing to risk colliding with its rivals to secure them.
4.To the Damascus Govt , pushing eastward to the border is paramount. Its troops at Deir el-Zour have been under siege by the Islamic State since 2014 and are in desperate need of relief. Their plight has attracted considerable attention among their loyalist allies, and the garrison's collapse is one last casualty Assad administration can scarcely afford.
5.Contrary to the common misconception that Damascus seeks to maintain its hold only on the country's more populated areas in the west, loyalist troops have spent much effort and many resources in trying to stake claims across the nation. One need only look at the costly endeavors of supplying and reinforcing troops in Deir el-Zour and al-Hasaka province, deep within rebel territory. Linking up with outposts in the far east and northeast is vital to the Syrian government's ambitions of reclaiming control of its country, not to mention the abundant energy and agricultural resources scattered throughout the region.
6. Kurdish forces supported by the US would try to capture and retain as much land as possible which may include main city of Ar -Raqqa situated just in the north of the Euphrates river. The river may be an important boundary between Kurdish and the Govt forces for quite sometime with ISIS vacating Ar -Raqqa and running across the river to Iraq. Kurdish forces with US support will try to secure as much land as possible in the north and east so as to call the shots for Kurdish autonomy in near future .
7.Assad's biggest ally, Iran, has a different goal in mind though. Hoping to bolster its logistics and force projection capabilities in the area, Tehran aims to clear a path from the Iranian capital to Damascus and the Mediterranean coast — something the loyalist push toward the border would help to achieve. As it stands, Iran has been forced to fully rely on sea transport (which is vulnerable to interception by the Israeli navy) and air transport (which has limited capacity and is difficult to conceal) to supply loyalist troops in Syria and Hezbollah militants in Lebanon. A land bridge would change that, substantially increasing the amount of materiel and personnel Iran can send west while forming a robust territorial link across the Middle East.
8. Iran has already begun to advocate an ambitious road project connecting its capital to Syria's, but it will only be of use if its Syrian partners are in control of the Iraqi border. Russia, meanwhile, has less to gain from winning the race than either of its coalition partners. Though it is still deeply involved in the eastward offensive, it has remained measured in its support. Unlike Iran, Russia has no pressing strategic need to blaze a path to the Iraqi border. But that doesn't mean the operation hasn't presented it with an opportunity to exact concessions from the United States. In fact, the U.S. military has already repeatedly reached out to Russian troops through their established deconfliction communication channel to keep Iranian-backed loyalist convoys from getting too close to its positions. It is unclear, however, just how much influence Russia has over the Iranian and loyalist fighters heading east; on several occasions they refused to stop or back away from U.S. troops, despite supposed attempts by the United States and Russia to set up a deconfliction zone near the Jordanian border.
9. Across the battlefield, the United States has stayed focused on its primary objective of defeating the Islamic State. The loyalists' steady movement eastward is thus a concern to Washington only in that it could interfere with the U.S.-led coalition's efforts to eradicate the extremist group from the country. Currently these efforts are divided into two operations: the offensive on Raqqa, spearheaded by the Syrian Democratic Forces ( Kurds), and the slow northeastward crawl toward the Euphrates River Valley, led by rebel groups such as Maghawir al-Thawra. As loyalist troops draw ever nearer to these areas, the risk of clashes with U.S. forces or disruptions to rebel operations in the region will steadily rise. In fact, a few notable incidents have already occurred. Within the past few weeks, loyalist artillery attacks and airstrikes have reportedly hit the positions of U.S.-backed Syrian Democratic Forces near the strategic town of Tabqa, which anchors the western flank of the rebel advance on Raqqa. On June 18, the United States shot down a Syrian government Su-22 warplane after it struck rebel forces near the town. The following day, Russia announced the suspension of its deconfliction communication channel with U.S. forces and threatened to target coalition aircraft in the airspace west of the Euphrates.
10. To the south, near the Jordanian border, the United States has thrice struck several IRGC-supported units closing in on its positions around al-Tanf, and a U.S. fighter jet shot down an Iranian drone after it targeted U.S. military positions in the area. A Three-Legged Race As Syrian troops surge toward the border, their attack will be three-pronged. The first element, spearheaded by an elite loyalist unit known as the Tiger Forces, will push past the Syrian Democratic Forces in Raqqa as it moves to the southeast. The second (and perhaps most critical) prong is made up of Russian- and Iranian-backed loyalists advancing along the M20 highway from Palmyra to Deir el-Zour. Since capturing Arak on June 14, this force has gained momentum. If it is able to reach Deir el-Zour before its competitors, it will be able to dig in in eastern Syria and connect to the Iranian road being built from Tehran to Damascus. The final prong consists of loyalist troops rushing toward the al-Tanf crossing, which rests near the intersection of the Syrian, Jordanian and Iraqi borders and sits on the all-important Damascus-Baghdad highway. So far, however, U.S. forces in and around the border crossing have denied the Syrian government access to it.
11.The Final Sprint The U.S.-led coalition and its rebel allies have certainly proved an annoyance to loyalists in eastern Syria, but they likely won't be an insurmountable hurdle on the path toward the border. For one, the Syrian Democratic Forces probably won't be free of their assault on Raqqa for several more months, giving loyalist troops moving toward Deir el-Zour a considerable head start. For another, though the arrival of al Assad's forces, accompanied by Soleimani, at the Iraqi border east of al-Tanf was largely a propaganda stunt given the distance they were from any major highway , including the Iranian road under construction — it highlighted the rebels' tenuous grip in the area. The fact remains that the loyalists, at present, stand a better chance of reaching and seizing the Islamic State posts left along the Euphrates River Valley than the U.S.-backed rebels.
12.No matter who wins the race to the Iraqi border, the biggest danger to all contenders over the next few months will be the growing threat of clashes between loyalist troops and U.S.-backed rebels in the frantic struggle for territory. At a time of heightened tension between Washington and Tehran, such skirmishes could further fuel their animosity toward each other. The IRGC has already alleged that Washington masterminded the twin terrorist attacks in Tehran on June 7, while the United States is reportedly mulling new sanctions against Iran. So, although the fight against the Islamic State may be waning with the extremist group's strength, a new and equally lethal battle could arise from its ashes if the powers involved in eastern Syria are not careful to effect a speedy ceasefire following a settlement.