A new coalition of armed opposition groups in northeastern Syria has launched an offensive against the Islamic State of Iraq and the Levant (ISIL) group in the province of Hasakah, as part of it's strive to eradicate the group from the entire country.

The Syrian Democratic Forces (SDF), which was formed in mid-October as an alliance among various ethnic factions, including Kurdish, Arab and Assyrian rebels, started attacking ISIL strongholds in Hasakah on Friday night.

"We declare the first step of our military action within a plan of liberating the whole Syria from the terrorist gangs," the Syrian Observatory of Human Rights (SOHR), quoted the group as saying in a statement.

Sherfan Darwish, the spokesman for the rebel group Burkan al-Furat - which is part of the SDF - told the AFP news agency that the coalition has targeted ISIL-held towns in Hasakah, including Shadadi and al-Hol.

He also said the fresh operations are receiving backing from US-led coalition air strikes.

In a video statement published online, the Kurdish People's Protection Unit (YPG) - a powerful armed group that is part of the alliance - also confirmed the beginning of the offensive.

In addition to Arab and Kurdish rebel groups, the SDF also includes the Syriac Military Council, a Christian faction led by ethnic Assyrians.

The Syrian coalition said in its first official statement - released on October 11 - that it was established with the aim of creating "a unified national military force for all Syrians" and bringing democracy to the country.

The alliance does not include more conservative Syrian opposition groups, such as Ahrar al-Sham and Nusra Front.

Source: Al Jazeera and agencies