Was Jordan involved in recent Syrian rebel-IS border battle?

Syrian rebels have seized control of an Islamic State group controlled town on the Syria-Iraq border, with apparant Jordanian support, activists have said.

US-trained fighters from the New Syrian Army and Free Syrian Army faction the Southern Front crossed into Syria from Jordan and took control of al-Tanf which lies close to Jordanian territory.

With cover from the anti-IS air coalition, the rebels killed one extremist fighter and wounded several others.

The border crossing is said to link Palmyra city and its historical site with IS' Iraqi territories. 

By the end of Saturday, IS claimed to have won back the border area.

Given the small number of fighters involved in Saturday's operation, the brief rebel victory over IS could be described more as a commando raid rather than land grab.

"The FSA military factions are competent to wipe out IS from Syria [if] the international community is serious about backing and providing them with a range of weaponry," said Omar Abu Layal, CEO of media group Deir Ezzor 24.

The action so close to the Jordanian border - and launched from its own turf - makes it almost inevitable that Amman had a hand in the operation.

It also coincided with rising nationalist sentiments in the kingdom following an IS scare in the northern city of Irbid.

Jordan also recently welcomed a US dispatch of Black Hawk helicoptors to protect its border from potential IS attacks. This too highlights Amman's current preoccuption with security, given extremist activity in neighbouring countries - in Syria, Iraq, Egypt and Saudi Arabia.

The involvement of the Jordanian-backed Southern Front also appears significant. The rebel group operates in Syria's southern Daraa province and many fighters have close family ties over the border in Jordan.  

The group is also said to have leaders based in Jordan, and the kingdom has hosted training sites for anti-regime rebels.

Analysts believe that Amman might be looking to use these FSA brigades to fight IS, which would coincide with a recent clampdown on jihadi-extremists in the kingdom.

The operation also took place just days after Jordanian troops battled IS militants in Irbid city, not far from the Syrian border.

Jordan is a key ally in the US-led coalition against IS and has concerns about growing extremist sentiments among its population.

It launched retaliatary air raids against IS in early 2015 after one of its pilots was brutally murdered by IS after his capture in Syria.

Amman also executed a woman linked to Al-Qaeda in Iraq's 2005 Amman bombings in what looked like a blunt message of revenge to the extremists. 

King Abdullah appears to deal with extremist threats through strong punitive actions, in whatever way is possible. But the palace also appears to work with Salafi leaders who speak out against IS. 

IS does not control any crossings into Jordan but al-Tanf lies comparitavely close to the Hashemite kingdom's borders. 

Amman might be looking to secure its margins with Syria to prevent infiltration by extremists in the future through anti-IS, rebel activity.

But the good news for Jordan is that the only other IS-linked group operating in Daraa province is the Yarmouk Martyrs' Brigade although appears weak and isolated from Abu Bakr al-Baghdadi's main territorial base.

Al-Qaeda affiliate al-Nusra Front also operate in Daraa, but they appear to have little appetite in attacking countries outside Syria, including Jordan.