(Refiles, dropping reference to Monday in third paragraph)
BEIJING, May 25 (Reuters) - A large group of ethnic Mongolians protested in front of a government building in northern China on Wednesday angered by inaction over the death of a herder, a rights group said, in a rare instance of unrest by the minority ethnic group.
The New York-based Southern Mongolian Human Rights Information Centre said that almost 2,000 students marched to the city government building in Xilinhot in China's Inner Mongolia.
They went "to urge the Chinese authorities to respect the rights and dignity of Mongolian herders" in Inner Mongolia, the group said in an emailed statement.
It was the latest in a series of protests by ethnic Mongolians in response to the "brutal" killing of a Mongolian herder by a Chinese coal truck driver, the group added.
Pictures posted on Chinese microblogging sites showed at least 100 people, many of whom appeared to be students, gathered in front of the city government.
Reuters was not able to independently verify the authenticity of the pictures or when they were taken.
The Xilinhot government did not answer repeated telephone calls seeking comment.
However, in a statement on its website (www.xlgl.gov.cn) on Wednesday, the government said police had arrested two Han Chinese for homicide.
The area around Xilinhot is home to many coal mines.
Decades of migration by the majority Han Chinese have made Chinese Mongolians a minority in their own land, officially comprising less than 20 percent of the roughly 24 million population of the Inner Mongolian Autonomous Region.
Inner Mongolia, which covers more than a tenth of China's land mass and borders Mongolia proper, is supposed to offer a high degree of self-rule. In practice, though, Mongolians say the Han run the show.
While protests in Inner Mongolia are far rarer than in Tibet or Xinjiang, two other parts of China with restive native populations, the Chinese government has still taken a tough line on Mongolians who seek greater respect of their rights.
Human rights issues in Inner Mongolia generally receive little attention, as the Mongolians lack a well-known overseas advocate like Tibet's exiled spiritual leader, the Dalai Lama. (Reporting by Ben Blanchard and Sui-Lee Wee; Editing by Nick Macfie)