A Ugandan Islamist rebel group known as the Allied Democratic Forces (ADF) carried out the attack in Eringeta, a town 55 kilometers (35 miles) north of the regional hub Beni, on Saturday afternoon, local officials said.
"The ADF has yet again plunged the people of Eringeti and its surrounding areas into mourning," regional official Amisi Kalonda told the Agence France-Presse news agency, speaking from the North Kivu capital Goma.
He said that 10 civilians were initially found, followed by 12 other bodies in surrounding villages on Sunday.
"The modus operandi is always the same," he said, adding that the victims were either killed with knives or machetes.
The Reuters news agency said several other violent incidents in towns that lie next to the Parc des Virunga, which borders Uganda.
At least 13 Hutu civilians were killed by an ethnic Nande militia on Sunday in Nyanzale, further south.
That attack was carried out in an apparent revenge for the killing of 17 Nande civilians last week by an ethnic Hutu militia, local activist Innocent Gasigwa told Reuters.
Hundreds of civilians have died in raids near Beni since October 2014. But while the government blames the ADF, analysts say others, including elements within the Congolese army, are involved.
Kabila digs heels in
Attacks have surged across the country in the past week alongside violent protests over President Joseph Kabila's failure to step down at the end of his constitutional mandate on Tuesday. At least 40 people died last week in the latest demonstrations.
The government says he will remain in office until an election can be organized in 2018.
Local mediators from the Catholic church hope talks between Kabila's ruling coalition and the main opposition bloc will produce a deal by Friday for Kabila to step down after an election in late 2017.
African and Western powers fear the violence could spark another conflict in a country where millions died between 1996 and 2003 in regional wars.
The central African country has not achieved a peaceful transfer of power since independence in 1960.
mm/kl (AFP, Reuters)