Jamaat Ansar al-Islam is a jihadist Iraqi insurgent group that claims to have expanded into Syria at least two years ago under the name "Ansar ul-Sham", supposedly participating from the start in the rebel operations to capture Mannagh airbase, which fell a year ago in an offensive spearheaded by the Islamic State. Ideologically, as I have documented previously, the group aspires to the establishment of a Caliphate, something neatly summarized in this pro-Jamaat Ansar al-Islam graphic. At the same time, it should be emphasized that Jamaat Ansar al-Islam is NOT an al-Qa'ida affiiate, despite its origins in the original al-Qa'ida-linked Ansar al-Islam of Iraqi Kurdistan. This was made most apparent when Jamaat Ansar al-Islam appealed to Aymenn al-Zawahiri in 2013 to restrain what was then Islamic State of Iraq, referred to as "your wing" in Iraq. Also note the group has an ongoing dispute with the Islamic State both in Syria and Iraq.
In light of such alignments, it was predictable that Jamaat Ansar al-Islam would not subsume itself under Jabhat al-Nusra's Islamic emirate project that is a predecessor to the Caliphate, but rather offer support to the jihadi "Jabhat Ansar al-Din" coalition that is similarly working on its own proto-state/Caliphate project. As I have noted before, all four constituents (Harakat Sham al-Islam; Jaysh al-Muhajireen; Green Battalion; Harakat Fajr al-Sham al-Islamiya) aspire to the Caliphate but are independent or have other alignments (e.g. the second to the Caucasus Emirate): the only possible surprise at first sight is Harakat Sham al-Islam but becomes explicable in light of the death of Ibrahim bin Shakaran in the spring who was the main link to al-Qa'ida Central (AQC), just as Abu Khalid al-Suri was the main link to AQC for Ahrar ash-Sham, hence the ambiguities in Ahrar ash-Sham's discourse while he was still alive over transnational/national distinctions in goals.
Below is a translation of the relevant parts of the recent Jamaat Ansar al-Islam Syria contingent statement supporting Jabhat Ansar al-Din.
[...]
"For after the announcement of the Jabhat Ansar al-Din coalition composed of:
- Jaysh al-Muhajireen wa al-Ansar
- The Green Battalion
- Harakat Sham al-Islam
- Harakat Fajr al-Sham al-Islamiya
And the announcement that the foremost intention behind the formation of this coalition is the establishment of the original law of God in liberated areas, to defend the precepts of religion and to support the oppressed among our people in the blessed land of al-Sham.
So we in Jamaat Ansar al-Islam in Bilad al-Sham bless this gathering of these allied battalions which we reckon for the best and we commend no one to God.
[...]"