In an apparent response to days of protests, Chinese authorities have declared martial law in parts of the northeast's inner Mongolia autonomous region, according to Amnesty International.

The region has long been the scene of ethnic tension between Mongolians, who have lived in the area for centuries, and the Han people, who arrived in larger numbers after the founding of the People's Republic of China in 1949. Han people are the majority ethnic group in China.

In the report released Friday, Amnesty International detailed protests in and around the city of Xilinhot.

CNN contacted officials in the affected areas, but they declined to comment.

According to the human rights organization, 2,000 Mongolian students took to the streets Wednesday in Xilinhot, in a show of solidarity with an ethnic Mongolian herder by the name of "Mergen," who was killed earlier this month when he was hit by a coal truck that was driven by ethnic Hans.

Amnesty reported that the drivers of the coal truck are both in custody of Chinese authorities.

In a clip posted to YouTube that purports to show that same demonstration, a large group of people, many of whom are young people wearing school uniforms, can be seen walking through the streets.

The students were marching toward the building that houses the regional government, shouting, "defend our land and defend our rights, according to the New York-based Southern Mongolian Human Rights Information Center. The group refers to the area as "southern" -- not "inner" -- Mongolia, and would like to see the region achieve independence or merge with Mongolia. (read more)