Cambodian government critic shot dead in Phnom Penh -Killing of Kem Ley comes at a time of heightened political tensions between Hun Sen’s administration and the opposition

Kem Ley, a prominent political analyst, was shot three times at a petrol station. A 38-year-old man has been arrested. Photograph: Heng Sinith

The killing of Kem Ley, 46, the head of a grassroots advocacy group Khmer for Khmer, comes at a time of rising political tension between the prime minister, Hun Sen, and an opposition hoping to challenge his grip on power in elections as soon as next year.

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Kem Ley was shot three times in a store at a petrol station in the Cambodian capital on Sunday, a police spokesman, Eng Hy, told Reuters. The spokesman refused to give further details.

The prime minister used social media to condemned the attack.

“I pay my condolences over the death of Kem Ley, who was shot by a gunman,” Hun Sen said on his Facebook page. “I condemn this brutal act.” He ordered an investigation into the killing and urged authorities to clamp down on firearms and explosives.

A 38-year old man has been arrested and admitted to killing Kem Ley in a dispute over money, Cambodia’s interior ministry said.

In a news conference, police presented the arrested man,who had blood on his head and shoulders, and was identified as Chuop Somlap, which means “meet to kill”.

“It’s hard to believe that this is his name. It may be fake,” Phnom Penh’s chief of police, Chuon Sovann, said. “We continue our investigation into people who are behind this.”

A witness said they saw Kem Ley’s body lying in a pool of blood on the floor of the store, with hundreds of onlookers gathered around. A water bottle and a mobile phone were nearby. Kem Ley’s pregnant wife, Pou Rachana, wept.

“I don’t know what happened. Somebody just called me and said that he’s shot,” Pou Rachana told Reuters. “He’s already dead,” she added, as investigators kept her away from the body of her husband.

Supporters gathered at the petrol station to prevent police from taking away the body, as some of them wanted to carry it on a march through the streets of the capital.

The US embassy in Phnom Penh said Kem Ley was one of Cambodia’s most prominent political analysts. Britain’s envoy called his death a serious loss to Cambodia.

Political tension is growing between Hun Sen and the opposition Cambodia National Rescue party (CNRP), which wants to take on the prime minister in local elections in 2017 and a general election in 2018.

A popular political commentator and researcher, Kem Ley was frequently critical of Hun Sen’s administration, having most recently commented on a report by anti-corruption pressure group Global Witness.

That report, which accused the prime minister and his family of having amassed $200m (£154m) in business interests. He Guardian UK