WASHINGTON (Reuters) - A Democratic Republic of Congo opposition leader called on Wednesday for the imposition of international sanctions against security officials responsible for the deaths of protesters in two days of demonstrations against President Joseph Kabila.

Congolese civilians walk past a house and vehicles which were burnt during anti-government protests to press President Joseph Kabila to step down in the Democratic Republic of Congo's capital Kinshasa, September 21, 2016. REUTERS/Kenny Katombe

“Without sanctions, they will continue killing people like mosquitoes,” said Moise Katumbi, a business tycoon and former Kabila ally. He was convicted in absentia of corruption and sentenced to 36 months in jail after he fled the country in June.

At least 37 protesters and six police officers died this week in the violence, according to Human Rights Watch. The government, which has blamed the opposition for the unrest and vowed to punish the ringleaders, put the death toll at 32, including four officers.

Katumbi, who put the number of dead at more than 50, denies the corruption charges, and said that African Union mediator Edem Kodjo, a former Togolese premier appointed to arbitrate between the government and opposition, should be replaced because he is biased toward Kinshasa.

He spoke to Reuters after some three dozen people died in clashes this week between police and protesters that erupted during demonstrations demanding that Kabila relinquish power when his second term expires in December.

Opponents of Kabila think he is trying to retain power in the mineral-rich country by delaying elections due in November or amending the Constitution to eliminate a two-term limit.

“President Kabila is just fooling everyone. He doesn’t want to go. He wants to remain in power and is killing his own people,” said Katumbi, who plans to run for president.

The United Nations should send an “independent commission” to the DRC to investigate the deaths of protesters, he said. Moreover, the African Union and international community should impose sanctions on senior security officials, including Minister of Justice Alexis Thambwe Mwamba, he added.

“If there are sanctions, there is going to be stability in Congo,” Katumbi said. “There is instability because there are no sanctions.”

The United States in June imposed “targeted sanctions” on a senior DRC police official, citing his role in what it called the violent repression of opposition protests and dozens of deaths.

The government denied the allegations.

Tom Perriello, the U.S. special envoy for Africa’s Great Lakes region, warned on Tuesday that Washington is ready to slap sanctions on more DRC officials “involved in abuses or violence.”