Syrian extremist group Fatah al-Sham Front on Sunday (October 9th) announced it has taken under its wing the radical Jund al-Aqsa group, AFP reported.

In the announcement, made via social media, Jund al-Aqsa also pledged allegiance to the group, formerly known as al-Nusra Front.

Jund al-Aqsa, recently labelled a terrorist organisation by the US State Department, has been locked in fierce clashes with other Islamist opposition groups in northern Syria's Idlib province.

The powerful Ahrar al-Sham group which has close ties to Fatah al-Sham Front has accused several members of Jund al-Aqsa of links to the "Islamic State of Iraq and the Levant" (ISIL).

Analysts said the move was expected to complicate things for Fatah al-Sham Front.

"Fatah al-Sham Front has pitched itself as a part of the opposition mainstream, but by taking Jund al-Aqsa into its fold, it has joined forces with a group that every single key opposition faction in northern Syria declared a front group for ISIL," said Middle East Institute analyst Charles Lister.

"That declaration was made as opposition groups, led by Ahrar al-Sham, were engaged in a substantial offensive to force Jund al-Aqsa out from all opposition territories," he said.

"So in short, Fatah al-Sham Front has illustrated that the protection of jihadists, even those so extreme as to acquire the (ISIL) label, are more worthy of protection than the very opposition groups it has tried so hard to embed itself within," he said.