An Uzbek militant fighting alongside the Islamic State (IS) group in Syria has called on militants to defect to IS from other groups, particularly Al-Qaeda's Syrian affiliate, Jabhat al-Nusra.

The militant, who calls himself Abu Hussein al-Uzbeki, makes the call in a six-minute video that was shared on social networks and Russian-language pro-IS websites this week.

The video bears the logo of Furat Media, an apparently unofficial IS media wing that is run by Russian-speaking militants, predominantly from the North Caucasus.

Abu Hussein says that he came to Syria from Uzbekistan in 2013 and fought in a Jabhat al-Nusra group led by another Uzbek, Abu Salah al-Uzbeki.

The main aim of the video message appears to be to discredit Jabhat al-Nusra. The Uzbek militant paints a negative picture of Jabhat al-Nusra, accusing the Al-Qaeda affiliate of lying to its members, treating foreign militants badly, and failing to help IS when that it was attacked by Syrian rebel factions in 2013.

In addition to urging existing Uzbek and other Russian-speaking militants in Syria who fight with Jabhat al-Nusra-affiliated groups to defect to IS, the message appears likely intended to direct new recruits who are thinking of fighting in Syria to join the IS militants rather than any other group.

Attacking Western-Backed Rebels

Abu Hussein says he worked in Jabhat al-Nusra's "special ops" and that he was ordered to attack a base of the Western-backed Free Syrian Army (FSA) near the Bab al-Hawa border crossing into Turkey.

"We were told that the FSA worked with America and that they were receiving money from them, i.e. for weapons. After a week, rumors started going around that it was IS that attacked the FSA, but in fact it was Jabhat al-Nusra," Abu Hussein said.

It is unclear when the Bab al-Hawa raid to which Abu Hussein refers took place. But there were reports in November 2013 that IS had raided FSA warehouses on the border crossing between Bab al-Hawa and Atmeh and taken them over.

The same warehouses were then seized by the Islamic Front Islamist rebel alliance in early December 2013.

Abu Hussein said Jabhat al-Nusra had told him that even though the FSA fighters were Muslims it was allowed to take their property and shed their blood.

But later, when IS started to fight against Jabhat al-Nusra, the Al-Qaeda affiliate told Abu Hussein that IS was wrong to kill Muslims.

Cannon Fodder

Abu Hussein said that he spent a year working as a reconnoiterer and intelligence operative for Jabhat al-Nusra and "noticed a lot of lies" that the group was telling.

The Al-Qaeda affiliate treats foreign militants who join its ranks worse than its native Syrian fighters, Abu Hussein said. He accused Jabhat al-Nusra of sending foreign militants to the front during offensives while letting local Syrian fighters keep to the back, and of failing to supply foreign fighters with sufficient ammunition during battles.

As a result, Abu Hussein says he started to argue with the group's leaders and eventually defected to IS.

The Uzbek militant called on fellow Russian-speakers who couldn't leave Jabhat al-Nusra to at least refuse to fight against IS.

Tawhid Wal Jihod?

While Abu Hussein does not refer to the name of the Uzbek-led group he fought alongside, it is possible he was part of an unnamed Uzbek faction within Jabhat al-Nusra.

Caleb Weiss, who tracks jihadi groups in Syria and Iraq for the Long War Journal, told RFE/RL that an Uzbek militant named Abu Saloh was the leader or a commander in an Uzbek group within Jabhat al-Nusra until sometime in 2014.

"I am not sure if the [Uzbek group] is the same one as the Seyfuddin jamaat, which is a jamaat [fighting group] the Islamic Movement of Uzbekistan used to or still does recruit for," Weiss said.

According to Weiss, Abu Saloh's group seems to have split off from Jabhat al-Nusra in 2014 to form a new Uzbek faction, the Tawhid wal Jihod (TWJ) group.

That faction is allied with Jabhat al-Nusra and has fought with it in a number of key offensives, including recent battles against Syrian government forces in Idlib Province.

One clue that TWJ is separate from Jabhat al-Nusra is the fact that it runs its own media group and its own flag. "They produce their own videos and in those, they go by Katibat Tawhid wal Jihod. If they were still in Nusra, I don't think they'd have this separate media production," Weiss added.

Uzbeks In Syria

Abu Hussein's video address includes information that is likely to upset Uzbekistan. The Uzbek militant specifically points out that he came to Syria from Uzbekistan.

Abu Hussein also suggests that he and other Uzbek militants are in Syria with their families and children.

One of Abu Hussein's criticisms in the video is that Jabhat al-Nusra withheld salaries and refused to pay for the children of militants like him who helped IS fight against the FSA.

The Uzbek authorities have previously acknowledged that Uzbeks are fighting in Syria and Iraq. But on several occasions, officials and clerics have said that these militants are either not Uzbek citizens but ethnic Uzbeks from elsewhere in Central Asia, or Uzbek citizens recruited in Russia.

Abdulaziz Mansur, the deputy chairman of the Muslim Board of Uzbekistan, told RFE/RL's Uzbek Service in March that only "two or three people" had traveled to Syria directly from Uzbekistan.

Mansur said that there were "about 200" Uzbeks in Syria, while a Kazakh analyst, Erlan Karin, has estimated that there are about 500 Uzbeks there.