Two Human Rights Party activists were killed in a motorcycle accident Friday in Takeo province as they rushed to attend campaign activities, officials said.

Mao Hoeurn, 51, vice president of the farmer affairs for the party, and his father, Mao Ban, 71, an activist for the party, died after their motorcycle collided with another motorcycle in Taphen commune, Tram Kork district.

The cause of death was not presumed to be politically motivated, police and human rights monitors said.

"As per our investigation, Mao Hoeurn was in a hurry and driving at a high speed, and a traffic accident took place," said HRP Takeo president Phan Soeurn. "We cannot conclude that this is a political issue."

Pok Pulrith, chief of traffic police in Takeo, said three other people were injured, one of them seriously, and are hospitalized in Takeo provincial hospital.

"This is the first time a political party activist died in an election campaign due to a traffic accident," he said.

In the first 6 months of 2008, nearly 20 people have died in Takeo traffic accidents, he said.