Cameroon's security forces killed 48 civilians as they responded to protests against the re-election of President Paul Biya, the world's oldest ruler, according to data shared with Reuters on Tuesday by two UN sources.The majority of the victims were killed by live rounds although several died from wounds sustained when they were beaten with batons and sticks, the two UN sources said.The 92-year-old Biya's government has not provided a death toll for the protests and a government spokesperson did not respond to a request for comment on Tuesday.Republican Senator Jim Risch of Idaho, chairman of the US Senate Foreign Relations Committee, accused Biya's government on Tuesday of staging a "sham" re-election, hunting down its political opponents and unlawfully detaining American citizens, including some from Idaho.He didn't specify who he was referring to."Cameroon is not a US partner, and poses economic and security risks to the American people. It's time to reassess this relationship before the blowback gets worse," Risch said on X. Biya was named winner of the election by a comfortable margin last week, receiving 53.66% of the vote against 35.19% for opposition leader Issa Tchiroma Bakary, a former government spokesperson who resigned from his ministerial post in June. Tchiroma had declared himself the winner shortly after the October 12 election, and protests erupted in various locations as early results showed Biya, in power since 1982, would get an eighth term.A civil society group known as Stand Up for Cameroon said last week that at least 23 people had been killed as a result of security forces cracking down on protesters.Nearly half of the deaths recorded by the UN occurred in Cameroon's Littoral region, which includes the port city of Douala where election-related protests last week were most intense.Three gendarmes also died in Douala, according to the UN data.There were 10 deaths recorded in the North region, the capital of which is Garoua, Tchiroma's hometown. Protests have died down considerably this week. Tchiroma called for a three-day national lockdown starting Monday, urging supporters to suspend activities and remain at home to show dissent at the election results.Biya is expected to be sworn in on Thursday.