Witnesses told news agencies that security forces on Sunday fired live rounds and tear gas in the capital, Kinshasa, to disperse demonstrators demanding an end to Kabila's 17-year rule.
The Catholic church had called for rallies around the country, despite a government ban on all demonstrations since September 2016, when anti-Kabila protests turned violent.
MONUSCO, the UN peacekeeping mission, said at least five people were killed on Sunday in Kinshasa and 33 others injured nationwide. Dozens of people were also reportedly arrested.
"I marched today for a simple reason: I want to bring up my children in a country that respects human rights," protester Pascal Kabeya, a 40-year-old market trader, told Reuters news agency where a few hundred had gathered in a suburb of Kinshasa.
A 16-year-old girl died after shots were fired from an armoured vehicle at the entrance to a church in the Kitambo area of the capital, Jean-Baptise Sondji, a former minister and government opponent, told AFP news agency.
A Reuters witness saw police and paramilitaries fire volleys of tear gas and shoot into the air outside the Notre Dame Cathedral in Kinshasa. At least six people were lightly wounded when they were struck by flying tear gas canisters, he told Reuters.
The latest round of anti-government protests on December 31, 2017 turned deadly, with protest organisers saying a dozen people were killed after taking to the streets to demand that Kabila step down.
"A lot of people are very frustrated with the political situation in the country and they're looking more to the church for guidance and leadership," Al Jazeera's Catherine Soi, reporting from Kinshasa, said.
In office since 2001, Kabila's constitutional term ended in December 2016, but he stayed on.
Under an agreement brokered by the Catholic Church, he was allowed to stay in office, provided new elections were held in 2017.
"That did not happen, the deal has expired, that's why the Catholic Church leadership is so angry," Soi said.
"[Catholic Church leadership are] saying they're going to continue calling on their faithful to come out in peaceful protests, demanding for electoral justice, demanding for politicians to respect the constitution and also for president Joseph Kabila to peacefully step down."
DRC authorities have said a vote would be held on December 23, 2018. But analysts, as well as Kabila's opponents, accuse him of wanting to stay in power.
Michael Tshibangu, a UK-based political analyst and president of the Association for Development and Democracy in Congo, said in early January the swift and forceful repression of December's protests showed "how determined [Kabila] is to stay in power.
"Everything we're seeing today shows that the DRC is going backwards. Kabila is in the process of establishing a dictatorship," Tshibangu told Al Jazeera.
The flare-up in violence has stoked fears that the vast, mineral-rich DRC could slide back into the wars that killed millions in the 1990s, mostly from hunger and disease.