DAMASCUS, Dec. 12 (Xinhua) -- Turkey-backed rebels in northern Syria on Wednesday expressed readiness to join Turkey's upcoming operation against Kurdish militia in eastern Syria, a war watchdog said.

Commanders of the Ankara-backed rebels said they are awaiting the orders from the "Turkish brothers" to launch an offensive which will cover areas between the eastern bank of the Euphrates River and the Iraqi border in the eastern countryside of Deir al-Zour Province, according to the Syrian Observatory for Human Rights.

The Kurdish-led Syrian Democratic Forces (SDF), its allied groups such as the People's Protection Units (YPG), and the Kurdistan Workers' Party (PKK) are all based east of Euphrates, while the Turkey-backed rebels are located on the western bank of Euphrates.

The Turkish intention to target the Kurdish militants, which are deemed as terrorists by Ankara, has for long been known despite the fact that the United States supports the Kurdish groups and even has bases in the eastern Euphrates.

Notably, Washington recently started to patrol the areas between the frontlines of both sides, as tension was brewing when Turkey-backed forces shelled the positions of Kurdish militias.

Meanwhile, the SDF and allied Kurdish groups have been in intense conflict with the Islamic State (IS) militants in areas held by the extremist group in the eastern Euphrates and the Turkish shelling pushed the Kurdish fighters to accuse Ankara of hindering the battle against IS.

In his remarks on Wednesday, Turkish President Recep Tayyip Erdogan said "it is time to realize our decision to wipe out terror groups in the east of Euphrates."

"We will start the operation to clear the east of the Euphrates of separatist terrorists in a few days," Erdogan said, referring to territory held by the Kurdish militias.

The areas that will be targeted have yet to be specified.

There has been no immediate comment from Damascus, which deems Turkey a force of occupation along with the United States.