KINSHASA (Reuters) - A Congolese court on Tuesday sentenced four pro-democracy activists to a year in prison for inciting protests against President Joseph Kabila, their lawyer said.

Kabila maintains a tight grip on the Democratic Republic of Congo despite his announcement in August that he will not defy constitutional term limits to seek a third term in elections due in December.

That decision calmed tensions that have roiled the country since he refused to step down when his mandate expired in 2016. But his opponents remain skeptical that the vote will be free and fair.

The activists were arrested on Dec. 30 as they mobilized residents of the capital Kinshasa to demonstrate against Kabila’s refusal to quit power. Security forces have killed dozens of people in similar protests over the last two years.

Carbone Beni, Grace Tshiunza, Mino Bopomi and Cedric Kayembe were convicted of incitation to civil disobedience, their lawyer Jacquemain Shabani told Reuters.

Beni is a coordinator of Filimbi, a youth movement whose members have been repeatedly detained by the security services.

Shabani said his clients would appeal their sentences, and should be released by Dec. 30 at the latest on account of time already served.

A fifth accused activist, Palmer Kabeya, was acquitted by the court.

Shabani and rights groups say Beni was badly beaten during his arrest and that he and the others were illegally held by the intelligence services without access to lawyers.

Government spokesman Lambert Mende said on Tuesday the activists should file a complaint with the prosecutor’s office if they had suffered abuse.

The United Nations has repeatedly criticized Congolese authorities for suppressing freedom of speech and using violence against peaceful protesters.

U.N. High Commissioner for Human Rights Michelle Bachelet warned earlier this month that widespread human rights violations by the government “endanger the credibility of the electoral process”.

The government has dismissed those charges and accused the United Nations and foreign governments of interfering in its sovereign affairs.