The authorities in Kinshasa banned the protest there, saying they did not have the resources to police it.
Eight people were killed Sunday and dozens arrested as security forces in DR Congo cracked down on Catholic worshippers who gathered at churches across the country to demand President Joseph Kabila leave power, a United Nations source said.
The delay has fuelled suspicions that Kabila will try to remove constitutional term limits that forbid him to run again, as presidents in neighbouring countries have done. The delayed poll is now scheduled for December 23 next year, heightening tensions in the restive nation.
Opposition parties, civil society, youth movements and about 150 Catholic churches support peaceful demonstrations.
Kabila succeeded his assassinated father Laurent Kabila in 2001 and refused to step down at the end of his second and final term in December 2016.
Ida Sawyer, Human Rights Watch Central Africa director, said Congolese security forces shot dead two men outside St Alphonse church in the Matete district.More news: Saudi Arabia releases 2 more princes in corruption case
A series of appeals by opposition leaders for protests this year have been easily suppressed by security forces but the Catholic activists' call has managed to unite almost all of Congo's fractious opposition.
Okundji wrote a letter to telecoms providers ordering them to suspend internet and SMS services by 6 p.m.in the capital Kinshasa (1700 GMT) until further instruction, although some users still had access more than two hours later.
Witnesses and churchgoers reported security forces firing tear gas and stun grenades at protesters gathered outside a number of churches in the capital.
One army officer threatened a team of AFP reporters covering the crackdown at St. Michael's church in Kinshasa. The parish priest asked worshippers to "return to their homes in peace because there is a heavy presence of soldiers and police ready to fire". A government statement said one policeman had also been killed.
Some 40 percent of Congo's population is Catholic and the church enjoys rare credibility with the public, even though its leadership has not formally backed Sunday's protests.