Police with rifles, tear gas, shields and electric batons put down a strike of 2,000 workers from a garment factory in Kandal province Thursday, leading to two serious injuries and the arrest of four protesters, workers and rights investigators said.

"The police accused us of disturbing public order or causing a traffic jam," said Yang Sarann, vice-president of Cambodian Garment Workers Democratic Union.

When police seized a microphone from workers demonstrating with a list of demands for the Fortune Garment and Woolen Knitting Company, a group of workers fought to take the microphone back, he said.

"It was probably a dozen who were snatching around with the authorities," he said. "So, [police] came over to fight, shock and handcuff."

Saang District Police Chief Moam Pich declined comment Thursday, as did Kandal Province Police Chief Iev Chamroeun.

Chheng Sophos, a rights worker for Licadho, said the workers had conducted a "peaceful strike."

"So, we are so sorry to see the authorities use violence to quell the strike, leading to some arrests," he said.

Striking workers and other protesters often clash with riot police, who use tear gas, electrical prods and, sometimes, water cannons to disburse assemblies.

This use of force to break up demonstrations is a serious rights violation, said Chan Saveth, an investigator for the rights group Adhoc who observed the strike.

"A crackdown by authorities on workers is very cruel, and it's imbalanced, as [demonstrators] have empty hands," he said.

Police seemed to have taken the side of Fortune Garment on Thursday, he said, speaking later as a guest on "Hello VOA."

Workers had been trying to push 12 demands, five of which had been solved at the time of the crackdown, he said. Instead of a resolution, workers were met with violence and a breech of their constitutional right to peaceable assembly, he said.

One caller to "Hello VOA" Thursday urged wider censure of "those who commit brutalities and just wait for orders like an automaton."