KINSHASA (Reuters) - Congo authorities swept through the southeastern mining hub of Lubumbashi on Thursday making dozens of arrests, local activists said, after at least 34 people died in protests against President Joseph Kabila.

Congolese opposition Union for the Congolese Nation (UNC) president Vital Kamerhe arrives for the talks between the opposition and government of President Joseph Kabila mediated by Congo's Roman Catholic bishops in the Democratic Republic of Congo's capital Kinshasa, December 21, 2016. REUTERS/Thomas Mukoya

Lubumbashi mayor Jean Oscar Sanguza told Reuters it was a “sweep up” operation targeting “criminals and bandits”, and that security forces were looking for arms. But local activists said they arrested young men suspected of supporting the opposition.

“As soon as you go by on the road and you’re a young man, you’re in a group of two or three, they (security forces) take you,” said Jean Claude Baka, regional head of activist group ASADHO, estimating 50 arrests since Thursday morning.

Human Rights Watch (HRW) said on Thursday that security forces in Democratic Republic of Congo had killed at least 34 people during protests this week against Kabila, who stayed in power despite his mandate running out on Tuesday with no fresh election organized.

Congo’s capital Kinshasa and other cities were convulsed by violent demonstrations on Tuesday against Kabila, who has been in power since his father Laurent was shot dead in 2001.

The protests, and a spate of disparate clashes between ethnic militias this week, have raised fears Congo is heading towards another major armed conflict. Millions were killed in wars in the massive central African nation between 1996 and 2003. The country has never had a peaceful transition of power.

In a bid to avoid that, talks between pro- and anti-Kabila politicians, facilitated by the Catholic Church, took place on Thursday, but it is unclear what they can achieve. The opposition has said a deal is possible only if Kabila commits publicly to stepping down and holds an election next year.

Jean Pierre Muteba, another Lubumbashi activist, put the numbers arrested there since Tuesday’s protests at 400.

ETHNIC VIOLENCE WORSENS

Western powers have condemned both Kabila’s failure to step down and the subsequent violent crackdown on protests, with former colonial master Belgium, France and Britain all warning of changed relationships with Congo. The U.S. has also condemned the arrests of protesters and the failure to hold elections.

The constitution bars Kabila from standing for a new term but his government says it cannot organize the presidential election, originally scheduled for last month, until at least April 2018 due to delays in registering millions of voters.

Opposition leaders say the delay is a ploy by Kabila to cling to power and ultimately change the constitution to run again. Kabila denies this but has declined to commit to not changing the constitution.

The government says 22 people were killed in the clashes nationwide, including a police officer, most of them by stray bullets or while looting.

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As the state’s legitimacy weakens, simmering conflicts are flaring up between armed groups in this vast, forested country of 70 million people and more than 200 ethnic groups.

Fighting in the eastern province of North Kivu on Thursday between Hutu and Nande ethnic militia killed 17 civilians and a police officer, army spokesman Captain Guillaume Djike said.

And at least six people were killed and 150 wounded this week in clashes between Pygmies and Bantus in southeastern Congo, a local activist said.

Map of deaths in Congo violence: