At least four people have been killed in three incidents during the election campaign, the Committee for Free and Fair Elections said in a report released Tuesday.
"We have seen many killings and intimidation and threats during the two weeks of election campaigning, which is a serious concern for us," said Comfrel Executive Director Koul Panha.
Cambodian People's Party activist Soth Song was killed in Kampong Speu July 1; CPP activist Lon Chork was killed in Kampong Chhnang July 6; and an opposition journalist, Khim Sambor, and his son were killed in Phnom Penh July 11, Comfrel reported.
Six people were killed in the election campaign in 2003, according to the report.
Comfrel also cited 16 cases of intimidation, especially against activists of the Sam Rainsy, Norodom Ranariddh and Human Rights parties.
The cases of intimidation were allegedly undertaken by local authorities and CPP activists and officials in various provinces, according to the report.
In one case, a death threat was made to Om Sara, who works for the Sam Rainsy Party's radio broadcast program Candlight, in Phnom Penh, according to Comfrel.
Mar Sophal, chief investigator for Comfrel, said the even though authorities have not credited threats with politics, the cases should be prosecuted by the courts.
Other irregularities in the report include 10 cases of gift-giving by the CPP, in Siem Reap, Kampong Chhnang, Prey Veng and Pursat provinces.
Political parties have also faced obstacles to their campaign, such as clashes between party activists, in at least four instances, Comfrel reported.
National Election Committee Secretary-General Tep Nitha said Comfrel's report signaled typical reporting by the monitor ahead of elections, but irregularities of this campaign have decreased from elections past.
In some cases, when irregularities are found to be apolitical, Comfrel does not change its reporting, he said.
In 2003, the NEC received around 600 election complaints, but this year only about 200 complaints have been registered, Tep Nitha said.
SRP lawmaker Son Chhay supported the report as accurate. There were even more cases of irregularities than reported by Comfrel, he said.
NEC was "busy" helping the CPP win the election, Son Chhay said, a charge Tep Nitha refused.
Son Chhay also accused police officials and civil servants of helping the CPP campaign, a breach of election law.