Rwanda-backed rebels reached the centre of east Congo’s second-largest city, Bukavu, on Sunday morning and took control of the South Kivu province administrative office after little resistance from government forces, many of whom fled the rebels’ advance.

Associated Press journalists witnessed scores of residents cheering on the M23 rebels in central Bukavu on Sunday morning as they walked and drove around the city centre after a days-long march from the region’s major city of Goma, 101km away, which they captured late last month. Several parts of the city, however, remained deserted with residents indoors.

The M23 rebels are the most prominent of more than 100 armed groups vying for control of Congo’s mineral-rich east and are supported by some 4,000 troops from neighbouring Rwanda, according to the UN.

It was not clear if the rebels had taken decisive control of the city of about 1.3 million people. Their presence in central Bukavu is an unprecedented expansion of the rebels’ reach in their years-long fighting with Congolese forces. Unlike in 2012 when they only seized Goma in the fighting connected to ethnic tension, analysts have said the rebels this time are eyeing political power.

Many Congolese soldiers were seen on Saturday fleeing the rebels’ advance into Bukavu alongside thousands of civilians amid widespread looting and panic.