Police said Tuesday they have detained dozens of people accused of violating a ban on protests against DR Congo President Joseph Kabila.
"Police have arrested and detained 34 people in Kinshasa," after Monday's protests, said national police spokesman Pierre-Rombaut Mwanamputu.
"Some wanted to breach the ban on a march, the others were preparing acts of vandalism."
Late Tuesday he said all of them had been released.
He gave no details of arrests in other parts of the vast country, where there is strong anger over Kabila remaining in office beyond the end of his mandate in December 2016.
Human Rights Watch said in a blog that over 80 people were arrested in Kinshasa and several other towns, including Bukavu in the east and Lubumbashi in the southeast.
The rights group told AFP that its figures include people who were arrested and subsequently released but was unable to say how many remained in detention.
The call by Democratic Republic of Congo's main opposition party for nationwide protests Monday appeared to have been ignored in Kinshasa, however, where people stayed home fearing violence after the authorities banned the rallies.
In the country's second city, Lubumbashi, Hubert Tshisuaka, the head of a local human rights group, told AFP he had no news of six people in a group of 24 detained by police on Monday.
In northeastern Goma, six people who tried to barricade roads were briefly detained and then freed, a local police source said.
The opposition is seeking to pressure Kabila, who has ruled since 2001, to implement a power-sharing deal brokered by the Catholic church to avert a crisis, by holding elections late this year.
Under the accord, Kabila agreed to share power ahead of the polls with a prime minister from the opposition.
But last week he named as premier a dissident member of the opposition, Bruno Tshibala. The main opposition has rejected this choice as being contrary to the letter and the spirit of the power-sharing accord.