Beijng, China (CNN) -- There is high tension in Inner Mongolia, China's strategic frontier region, where the death of a Mongolian has triggered rare street protests.

It is now witnessing ethnic discord between Mongolians, who populated the area for centuries, and the Han Chinese, who now make up 79% of the province's 24 million population.

It all started on May 10, when an ethnic Mongolian herder was struck and killed by a coal truck driven by Han Chinese. The herder, protesting against the coal mining activity, had tried to stop trucks from crossing into his traditional pastureland.

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The hit-and-run incident triggered anger that festered for weeks as Mongolians used mobile phones and the Internet to circulate pictures of the herder's death.

Five days later, a forklift driver allegedly struck and killed Yan Wenlong, a young Manchu worker, who was among a group of people protesting pollution in a coal mine.

Last week, some 2,000 Mongolians, spearheaded by students, took the anger to the streets in Xilin Gol.

They marched toward government offices, chanting "defend our land and defend our rights".

"People demanded legal rights for Mongolians, for herders," said Enghebatu Togochog, director of the New York-based Southern Mongolian Human Rights Information Center (SMHRIC). "They didn't mention higher autonomy or independence. Their goals are practical, so the government can't find an excuse to crack down hard on them."

Still, Chinese officials moved swiftly to quash any rebellious tendencies. They deployed riot police and paramilitary troops to disperse crowds and patrol the streets. They blocked access to social media sites and text-messaging services, apparently to prevent protesters from regrouping.

They tried "soft" tactics, too. Hu Chunhua, Inner Mongolia's 48-year-old party chief, met with students and teachers, assuring them that the Han Chinese suspects would be prosecuted promptly and severely.

Hu promised to look into regulating mining activities, which are dominated by Han Chinese, and to look into the impact of mining on the environment, the traditional culture and the livelihood of local residents. He also sacked the communist party chief of Xilin Gol, where the incident took place.

Human rights activists say the discord in Inner Mongolia reflects the failure of China's policies toward national minorities.

"China's policies toward ethnic minorities aim at assimilating them, while facilitating the exploitation of the natural resources found on their territories," says Nicholas Bequelin, senior researcher at Human Rights Watch. "These policies are accompanied by systematic political and cultural suppression, economic marginalization and institutionalized discrimination."

Mongolian activists say constant migration of Han Chinese, the country's dominant ethnic group, is diluting their language, culture and livelihood.

Mongolians also complain that their traditional grazing lands have been ruined by mining and desertification.

"People want more freedoms," says Enghebatu Togochog of SMHRIC, "We think the authorities should let people decide if Mongolians want independence, higher autonomy or staying in the People's Republic of China. But the government obviously doesn't accept the concept of self-determination."

Occupying 12 per cent of the country's land mass, Inner Mongolia sits atop rich reserves of coal, oil, gas, minerals and rare earth resources. It is China's top coal producer, accounting for about one-fourth of the country's coal production.

But human rights activists say that many Mongolians are left out of China's lucrative economic boom, living in remote grasslands where the markets and education are typically inaccessible.

"In fact tensions have been running high under the surface for many years and conflicts between herders and new settlers have long been an everyday occurrence," says Bequelin of Human Rights Watch. "The real factors behind the protests in Inner Mongolia are the long-standing suppression of the Mongols' basic rights and their gradual eviction from the grasslands."

Chinese officials and academics insist the protests reflect local unhappiness over loss of land, not necessarily a clash between ethnic Mongolians and Han Chinese. Hao Shiyuan, a professor the the Institute of Ethnology and Anthropology, believes "these protests are a conflict derived from economic development, as seen in similar protests against land acquisition in southern China."

In any case, last week's flare-up could not have come at a more sensitive time.

The Communist government is still dealing with the aftermaths of the ethnic violence that erupted in Tibet in 2008 and in northwestern Xinjiang in 2009.

Now it is in the midst of a harsh crackdown on political dissent, prompted by anonymous calls in microblogs for a "Jasmine" revolution in China.

Jitters heightened this week as Beijing braced up for the 22nd year anniversary of the bloody suppression of the Tiananmen protests on June 4.

Ethnic conflict in Inner Mongolia has shaken up the Chinese officialdom.

On Monday, the communist party's powerful Politburo convened a special meeting and called for improved "social management" to ease social tension, promote fairness and harmony.

"Local authorities (in Inner Mongolia) are trying to protect the local environment and to balance environmental impacts and economic development," says foreign ministry spokeswoman Jiang Yu.

She blames "outside forces" for the exacerbated tension. "Some people overseas try to play up the issues and the motives," Jiang says. "Their attempts will not succeed."

Fearing trouble, cyberspace censors are now blocking any mention of "Inner Mongolia" in Chinese microblogs and social networking sites.