A Kurdish-Arab coalition fighting the Islamic State in Iraq and the Levant (ISIL) has announced the creation of a political wing after a two-day conference in Syria's northeastern town of Al-Malikiyah.

The formation of the Syrian Democratic Council was approved Thursday at the meeting, which was attended by the Democratic Union Party (PYD), the largest Kurdish group, and its armed wing, the YPG.

The PYD was not invited to a separate meeting of Syrian opposition groups that ended in the Saudi capital, Riyadh, on Thursday.

The groups' allies, the Syrian Democratic Forces (SDF), were not invited to the conference in Saudi Arabia, either.

"The participants agreed on the creation of the Syrian Democratic Council, the political branch of the Syrian Democratic Forces," a statement issued at the end of the conference read.

The SDF, formed in October, groups the powerful YPG with smaller Arab and Christian armed groups in a coalition intended to confront ISIL.

In other news from Syria's mainly Kurdish northeastern region, the death toll from Thursday's triple suicide car bombing attack has risen to 26, according to a local monitoring network.

The Syrian Observatory for Human Rights said the initial toll from the attack in Tal Tamr, in Hasakah province, had risen from 12.

Rami Abdulrahman, the Syrian Observatory's director, said one of the bombs detonated next to a post manned by Kurdish security forces and that members of the force were believed to have been killed, though he did not know how many.

Another blast took place in front of a hospital, Abdulrahman said, adding that four women and a doctor were killed.

He said dozens of people had been injured in the blasts and warned that the death toll could rise.

In a statement on social media, ISIL claimed responsibility, saying three of its members blew themselves up in their explosives-rigged vehicles. It claimed 60 people had been killed and dozens injured.

Tal Tamr, in Hasakeh's Khabur region, is controlled by Kurdish forces and has been targeted in the past by ISIL.

In February, ISIL overran much of the Khabur region and abducted at least 220 Assyrian Christians during the offensive.

But Kurdish fighters from the YPG subsequently recaptured the area, and dozens of the ISIL-held hostages have been released in recent months.

On Wednesday, about 25 Assyrian hostages, including two children, were freed by ISIL, according to the Assyrian Human Rights Network.

Al Jazeera and wire services