GOMA, Congo — Rwanda-backed rebels in eastern Congo entered the region’s second-largest city of Bukavu on Friday, local and civil society leaders said, the latest ground gained since a major escalation of their yearslong fighting with government forces.

The M23 rebels entered the city’s Kazingu and Bagira zone and were advancing towards the center of the city of about 1.3 million people, according to Jean Samy, vice president of the civil society in South Kivu. He reported gunfire in parts of the city.

Videos posted online appeared to show rebels marching toward the Bagira area.

Hours earlier, the rebels had claimed to have seized a second airport in the region, in the town of Kavumu, following a days-long advance, while the U.N. warned that the recent escalation of fighting with government forces has left 350,000 internally displaced people without shelter.

The M23, which is supported by about 4,000 troops from neighboring Rwanda, took control of eastern Congo’s biggest city, Goma, in late January.

— The Associated Press