Two major groups on the ground in Syria that have received assistance from the United States, the People's Protection Units (YPG) and the Free Syrian Army (FSA), are trying to destroy Daesh, but instead of being allies they are in fact fighting against each other.

Simmering tensions escalated earlier this month when rebels affiliated with the FSA launched a guided TOW missile on a YPG position in Aleppo in what appeared to be the first attack of its kind. The Kurds said that the weapon was provided by the US.

© REUTERS / Abdalrhman Ismail Men inspect damage after an air strike on Aleppo's rebel-held al-Shaar neighbourhood, Syria June 8, 2016

There is a lot of bad blood between the Kurds and the FSA since the two groups have conflicting priorities. The Kurds are trying to receive greater autonomy, while the Syrian rebels are concerned that the former will fracture the country. In addition, the FSA has been trying to remove Bashar al-Assad from power, while the Kurds do not see him as an enemy.

The FSA has also accused the Kurds of ethnic cleansings in Arab areas freed from terrorists. The Kurds have denied these claims.

Arabic scholar Leonid Isaev of the Carnegie Moscow Center singled out three main opposition groups in Syria, based on the capital where they were created – the Riyadh group, the Moscow group and the Cairo group. They all were formed following the same logic: foreign-based opposition groups viewed as legitimate by the international community have been paired with forces located in Syria.

"Both sides needed each other although they did not really trust each other," he added. "Various committees and councils of Syrian expat politicians were trying to receive backing from groups who are taking part [in the war] and hold certain areas under control. The latter were also interested in having someone to represent them at the Geneva talks."

As a result, the Riyadh group, as the analyst referred to it, has been supported by the Islamic Front and the Free Syrian Army. The so-called Moscow group has been backed by the Syrian Social Nationalist Party (SSNP), while the Cairo group has ties to the Kurds, primarily the Democratic Union Party (PYD) and its military wing, the YPG.

"The Free Syrian Army gradually united other opposition groups and movements that are active in Syria. As a result, by August 2014, they formed the domestic part of the Riyadh group, the Syrian Revolutionary Command Council (SRCC) that includes more than seventy different factions," Isaev detailed.

© AFP 2020 / Free Syrian Army members train on the outskirts of Idlib, Syria (File)

The SRCC itself has been plagued by major differences between Islamists and secular groups, with the latter discontent that so many radicals were invited to join the council. The rift even prompted the Jordan-backed Southern Front of the Free Syrian Army to leave the organization.

Relations between some SRCC members and al-Nusra Front proved to be an additional challenge.

"Technically every group on the council was supposed to be against [al-Nusra Front] since they are all allies of the US-led counterterrorist coalition. But some groups, particularly the Islamic Front and the Aleppo-based Levant Front, remained al-Nusra allies even when they joined the SRCC," the analyst explained.

Needless to say, secular groups were not happy with this relationship.

The Cairo group, the analyst noted, has political leverage due to its close ties with the best Kurdish fighters. For their part, the Kurds view the group as an opportunity to communicate with the West and the Arab countries.

"The Kurdish issue has to a large extent become a stumbling block that prevented the Cairo group from taking part in the Geneva talks. At first, the group boycotted the negotiations because members of the Riyadh group were against the Cairo Kurds. But later Haytham Manaa, who heads the Cairo group, and PYD leader Saleh Muslim decided to go to Geneva as part of the Moscow group," he observed.