GOMA, Congo — Panic swept through eastern Congo’s second-largest city Saturday as residents fled by the thousands, scrambling to escape the looming advance of Rwanda-backed rebels.

The morning after M23 fighters entered the outskirts of Bukavu — a city of about 1.3 million people that lies 63 miles south of rebel-held Goma — some streets were flooded by residents attempting to leave and looters filling flour sacks with what they could find.

A pall of silence set in later in the day as residents and business owners braced for what comes next.

Later Saturday, a relative calm had returned to Bukavu as gunfights stopped after Congolese troops exited the city and drove south, Bukavu resident Alexis Bisimwa said.

“We’re no longer waiting for the crackling of bullets as we were during the day,” he told The Associated Press by telephone.

Most people waited in their home, shocked as corpses burnt to ash lay strewn in the streets — casualties of the looters who filled the vacuum left by Congolese soldiers earlier abandoning their posts.

“They set fire to the ammunition they were unable to take with them,” said Alain Iragi, among the residents who fled in search of safety Saturday.

Reports and social media videos showed the region’s factories pillaged and prisons emptied while electricity remained on and communication lines open in most places.

“It’s a disgrace. Some citizens have fallen victim to stray bullets. Even some soldiers still present in the city are involved en masse in these cases of looting,” a 25-year-old resident of a neighborhood being looted said.

The Congo River Alliance, a coalition of rebel groups that includes M23, blamed Congolese troops and their allies from local militia and neighboring Burundi for the disorder in Bukavu.

“We call on the population to remain in control of their city and not give in to panic,” Lawrence Kanyuka, the alliance’s spokesperson, said in a statement Saturday.

M23, a rebel group backed by about 4,000 troops from neighboring Rwanda, is the most prominent of more than 100 vying for control of Congo’s mineral-rich east.

Congolese authorities and international observers have accused it of sexual violence, forced conscription and summary executions.

M23’s southward expansion encompasses more territory than rebels had previously seized and poses an unprecedented challenge to the central government in Kinshasa.

The rebellion underway has killed nearly 3,000 people in eastern Congo and stranded hundreds of thousands of displaced. At least 350,000 internally displaced people are without shelter, the U.N. and Congolese authorities have said.

The rebels Friday also claimed to have seized a second airport in the region, in the town of Kavumu outside Bukavu.

The AP couldn’t confirm who was in control of the strategically important airport.