By Maya Gebeily BEIRUT (Reuters) -Syrian rebels opposed to President Bashar al-Assad said on Friday they had reached the heart of the northern city of Aleppo, after a surprise sweep through government-held towns and nearly a decade after having been forced out of the city.

Syrian rebels clashed with government forces in Aleppo for the first time since 2016 as they swept through the country's largest city in a surprise offensive that forced people to flee and added further instability in the already war-battered nation.

A rebel commander said a fall in Iran-backed manpower created an opening this week's assault. Iran's ally Hezbollah has suffered big losses to Israel.

Thousands of Syrian insurgents have pushed on with their advances on government-held areas in the country’s northwest

Rebel forces in Syria have taken control of several neighbourhoods in the country's second-largest city, Aleppo, according to the UK-based monitoring group Syrian Observatory for Human Rights (SOHR).

Former U.S. Ambassador to Syria, Robert Ford, explains what the latest breach by insurgents into Syria's second-largest city Aleppo means for the ongoing Syrian civil war.

Syrian armed rebels have entered Aleppo just three days into their surprise offensive, marking the first time they have set foot in the country’s second largest city since government forces recaptured the city in 2016.