Chinese authorities have arrested 22 people in Inner Mongolia for protesting over a land dispute, a rights group said Tuesday, in the latest case of ethnic strife to rock the northern region.

The arrests occurred on Monday after hundreds of ethnic Mongols living near Tongliao city tried to stop a vehicle belonging to a forestry firm that they claim has illegally occupied their land, the group said.

"Police violently beat up the protesters with batons. Some were bleeding, some were beaten down on the ground," the US-based Southern Mongolian Human Rights Information Center (SMHRIC) quoted a protestor as saying.

A local government official reached by AFP denied the confrontation was violent.

"I know there is a land dispute, but no violent clashes happened," said the official of the township which governs the area. Another township official denied any such incident had occurred.

In May last year, the vast region experienced a wave of demonstrations sparked by the killing of a protesting Mongol herder. There has long been resentment at Chinese rule and exploitation of the area's natural resources.

The Mongol herder was run over by a coal truck driven by a member of China's dominant Han ethnic group as he and others sought to block a convoy of vehicles. The driver was later sentenced to death.

According to SMHRIC, villagers in the latest incident said they had protested at the local level for months and even tried to petition the central government in Beijing over the alleged land grab.

But this time, the local government responded with force, dispatching more than 80 paramilitary soldiers to put down the protest, it said.

Confrontations between Han Chinese and Mongols have laid bare simmering discontent in Inner Mongolia, a vast region that separates China from the country of Mongolia.

Many Mongols complain Chinese culture is swamping their way of life, and a government policy to move herders off the steppe to preserve the environment is widely considered a pretext to seize land, further fuelling resentment.