The US is being pushed to take action on Syria’s southern front.

Dynamics in the southern front in Syria have reached a tipping point. Russian-Israeli coordination is taking precedence over the ceasefire agreement that US President Donald Trump and Russian President Vladimir Putin reached on the sidelines of the G20 summit last year.

Iran and the United States are both facing increasing pressure in the area, while both the Syrian regime and the Syrian armed opposition are on alert over a potential clash to settle the question of who controls the southwest border areas.

US’ ambivalent role on the southern front

The US used to play a significant role on the southern front. The Amman-based US-led Military Operations Center (MOC) was providing training and weaponry to a number of Free Syrian Army (FSA) groups operating in southwest Syria between 2014 and 2016.

The US and the FSA groups did not see eye to eye on whether the priority was to fight the so-called Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group or the Syrian regime. Ultimately, when Washington signed the ceasefire agreement with Moscow, it closed the supply lines to the southern front.

Jordan sealed off its border with Syria after it was overwhelmed by the large number of refugees fleeing the Syrian war. Since then, the southern front became a low priority issue for the Trump administration compared with the high-level US diplomatic and military engagement on the northern front.

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But the Russian-Israeli coordination, which has increased to unprecedented levels in recent weeks at the expense of both the US and Iran, has compelled the Trump administration to come back on the scene.

It is currently trying to pressure Russia to fulfil its commitments from the July 2017 ceasefire. The negotiated plan reportedly trades the US vacating al-Tanf base for withdrawing Iranian forces and their backed militias from southwest Syria. Al-Tanf is located in the southern part of Homs governorate, on the border with Iraq and was used by US forces to train Syrian rebels in the past. The Syrian regime and its Iranian allies have hoped to take control of the area and the al-Waleed border crossing for a while in order to open the Baghdad-Damascus highway.

The US offer to Russia includes keeping all Syrian and foreign militias 20 to 25km away from the Jordanian border, transferring the opposition fighters and their families to Idlib, reopening the Nasib border crossing (near Deraa city) with Jordan, and forming a joint US-Russian mechanism to oversee the agreement.

The key US interlocutor, Assistant Secretary of State for Near East Affairs David Satterfield, is on his way out and will soon be replaced by David Schenker whose views on Syria are more aligned with Secretary of State Mike Pompeo and White House National Security Adviser John Bolton.

It is not clear whether this reported US offer will stand. Moreover, if the US does not vacate al-Tanf, Iran and the Syrian regime will most likely attempt to block any deal on the southern front.

Two scenarios for the US

Washington has a rather limited set of options. The first scenario would see the US taking a backseat and giving up all influence in southwest Syria in return for keeping Iran away from the Jordanian and Israeli borders.

Russia will then exclusively dominate the rules of engagement in this area. Hence Israel will be able to blame only Moscow in case of any agreement violation. Washington will also leave once again the impression of giving up on allies, the FSA in this case, but US forces can instead focus their resources on protecting their assets in the friendlier environment of northeast Syria.

The second scenario would see the Trump administration opting to revive its role in the southern front. US fighter jets or drones could target Syrian regime attempts to expand territorial control in Deraa and Quneitra provinces. The US could also re-open the supply lines via Jordan to the FSA groups, which would technically mean re-escalation of the Syrian civil war.

The Pentagon wants to avoid both scenarios.

Russia-Israeli coordination

Putin is forcing the US’ hand in southwest Syria to somehow bring Washington back to the negotiation table. Moscow has sanctioned in the past few days the deployment of the Syrian army’s Tiger Forces to the outskirts of Deraa.

This caught the attention of the Trump administration. Pompeo spoke over the phone last Monday with his Russian counterpart Sergey Lavrov and Trump could potentially meet Putin ahead of the NATO summit in Brussels next month. Trump will most likely want to be involved in any Russian-Israeli deal in southwest Syria.

The lack of US-Russian coordination has weakened Jordan’s position in Syria and compelled it to realign its interests with Israel. Both Jordan and Israel agree that Iran and its militias should stay away from the border and from the occupied Golan Heights. Amman is asking Moscow not to initiate a confrontation that could cause another wave of Syrian refugees into Jordan. The FSA might face the difficult decision between voluntarily surrendering the border crossing and its surrounding area to the regime or fighting for survival.

The main contentious point between the concerned parties is whether Iranian forces and their militias are among the Syrian regime troops to deploy in Deraa. The hawkish Israeli defence minister denied that Iranians forces are disguised in Syrian uniform, which rather reflects the depth of the Russian-Israeli coordination.

Moreover, Damascus is sending Israel – via Moscow – the necessary guarantees to restore the 1974 ceasefire line in the Golan Heights. But Israel is asking for full Iranian withdrawal from all of Syria at a time when there is a crack in the Russian-Iranian alliance. This Israeli demand is an attempt to start from a high negotiating point to have Russia enforce additional restrictions on Iranian movements in Syria.

Despite the tense rhetoric on the ground, Moscow remains in full control of the reinforcements sent by the regime to the outskirts of Deraa. The Russian police is simultaneously supervising and protecting the regime forces as a guarantee for Israel and Jordan.

The intermittent skirmishes that happened this week between the regime and the FSA were limited, with no Russian involvement.

Both Washington and Moscow are pressuring their Syrian allies not to escalate. The Syrian regime deployment is meant to strengthen the Russian negotiation position and is restricted to the Jordanian border area only at this point, which means the Russian-Israeli agreement is yet to fully materialise

No matter what scenarios might unfold, the US has two options to become relevant once again in southwest Syria: to confront or engage Moscow. Otherwise, the US might become a bargaining chip in a looming deal between the rest of the parties involved.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.