Damascus: The US-backed Syrian Democratic Forces and allied militant groups on Tuesday unleashed a campaign against the de facto capital of the Islamic State (IS) in Syria`s Al-Raqqa province.
The move comes just days after the US and the SDF put forward a plan for capturing Al-Raqqa, Xinhua cited a monitor group as reporting.
Citing what it described as "trusted sources", the Syrian Observatory for Human Rights said the SDF, which is a newly formed Kurdish-led group supported by the US, along with fighters from Arab tribes, unleashed an offensive against IS positions in the northern countryside of Al-Raqqa province.
The province fell to the IS in late 2013 and was later declared by the group as their capital in Syria.
The fighters started moving toward northern Al-Raqqa from the southern countryside of the border city of Tal Abyyad and the countryside of Ein Issa in the northwestern rim of Al-Raqqa.
The SDF are engaged in major battles against the IS under heavy airstrikes from the US-led anti-terror coalition, said the Britain-based watchdog group.
The observatory, which depends on a wide network of activists on ground, said the offensive aims at its initial stage to strip the IS from a triangle connecting Tal Abyad, with the Division 17 and Ain Issa.
It added that the offensive in its initial stage does not include pushing deeper into Al-Raqqa.
General Joseph Votel, head of US Centcom, secretly visited northern Syria on Friday for 11 hours, during which he met commanders of the SDF and other US-backed rebel groups, including the Liwa Thuwar Al-Raqqa.
The visit was aimed at coordinating the US-led coalition and rebel plans in taking back Syria`s northern province of Raqqa.
Pan-Arab al-Mayadeen TV said in a special report on Sunday that a plan for unleashing an attack on Al-Raqqa was put forward during the meeting.
According to sources familiar with the situation, the TV said the attack is expected to be launched with the participation of 12,000 fighters.
The conferees also discussed the requirements of the military offensive and the needs of the fighting groups, said the report.
An agreement was reached to focus on the Arab fighters who will attack to alleviate the fears of Turkey from any expansion of Kurdish fighters near the Turkish borders, it said.
It said the meeting between Votel and the rebels came just days after a meeting between the Brett H. McGurk, the US Special Presidential Envoy for the Global Coalition to Counter IS, and Saleh Muslim, the head of the Kurdish Democratic Union in the countryside of Ayn al-Arab.
The report said the meeting discussed the same issue.
The 500 US soldiers, who have recently crossed into Kurdish areas in northern Syria, will directly take part in Al-Raqqa battle, said the report.
Even though the timing of the battle was not declared, the IS seemed to have anticipated the move, asking civilians in key areas in Raqqa to move toward IS-controlled towns in the countryside of that province.
Reports said the terror group also went on arrest raids for young men to oblige them to fight among its ranks.