Armed men burst into Democratic Republic of Congo's eastern city of Bukavu overnight on Wednesday, triggering clashes that killed 11 people and left the 1 million residents in lockdown.
Gunfire was heard around the city from about 1:45 a.m. (0245 GMT) but the fighting appeared to have stopped by the afternoon, local residents and a Reuters journalist said.
The city, which sits on the border with Rwanda and was at the centre of violence during two regional wars around the turn of the century, was last convulsed by fighting in November 2017 when the army clashed with troops loyal to a renegade general.
More than 120 rebel groups operate across large swathes of eastern Congo since the official end of the wars in 2003.
South Kivu province's governor Theo Kasi said security forces killed eight gunmen and captured 36 others, while one police officer and two soldiers were also slain.
"Thugs and uncivilized people disturbed the peace of our fellow citizens in some areas of the city of Bukavu," Kasi said, though he could not identify the assailants.
A local army commander blamed a new militia called the Coalition of Congolese Patriots for the Application of Article 64 (CPCA-A64) - a reference to a part of the constitution saying Congolese should oppose anyone exercising illegitimate power.
The commander, Bob Kilubi, said around 40 fighters entered the city from the north singing liberation songs.
"Some of them wanted to attack the military camp to loot the ammunition. The army prevented them," he told local Radio Maendeleo.
CPCA-A64 issued a manifesto in Bukavu on Oct. 7 demanding that President Felix Tshisekedi resign, saying he won the 2018 election fraudulently. Tshisekedi denies this.
The group, which Reuters could not reach for comment, did not appear to have claimed responsibility.