PHNOM PENH (Reuters) - Cambodian land rights protesters clashed with city security guards on Monday as demonstrators in the capital Phnom Penh called on the government to end forced evictions.

Land disputes are a highly contentious issue in Cambodia, where tens of thousands of people have been evicted to make way for foreign and domestic firms, prompting widespread protests, violent clashes and, in some cases, jail terms for those who refuse to move.

A video circulated on Facebook showed security guards punching and slapping protesters. Reuters couldn't independently verify the authenticity of the video.

The protesters, many holding models of homes over their heads, were marking World Habitat Day, which took place last week as a reminder of people's right to shelter.

Phnom Penh City Hall spokesman Mean Chanyada said that a journalist and a human rights worker were injured in the clash and that the use of violence was necessary to stop hundreds of demonstrators from marching forward.

"There was a small clash because the protesters didn't follow instructions of the authorities to gather only at one place," Chanyada told Reuters.

Licadho, a local rights group, called the attack "unacceptable".

(Reporting by Prak Chan Thul; Editing by Amy Sawitta Lefevre and Nick Macfie)