BEIJING (BLOOMBERG) - Chinese police are offering cash rewards for clues that could lead them to more than 100 people, as public demonstrations swept through cities in Inner Mongolia over the introduction of the Mandarin language in some school lessons.

The police bureau of Tongliao, a city in the autonomous region bordering Mongolia and Russia, published photos and detailed descriptions of dozens of people they accused of "picking quarrels and causing troubles" starting Wednesday (Sept 2).

They said the people had committed the crimes between Sunday and Tuesday, the same period the unrest broke out.

Horqin district police issued a separate notice calling for information on dozens of people.

The search comes as government efforts to change the language of instruction of some subjects to Mandarin from Mongolian have prompted parents and students to boycott classes and take to the streets in protest.

The authorities have used similar techniques to dilute the cultures of ethnic minorities in Tibet, Xinjiang and Guangdong.

Videos from human rights groups showed people chanting demands in Tongliao, which has a significant Mongolian population.

The rollout of Mandarin-language classes kicked off Tuesday, beginning with language and literature classes for selected grades.

It will later cover two other subjects - morality and law, and history.

President Xi Jinping has urged the overhaul of education in the three subjects where changes have taken place in Inner Mongolia in a bid to "safeguard ideological security".

Local education authorities said in a statement on Monday that Mandarin would only be used to teach the three subjects that are part of the new rollout, and that the current bilingual system of instruction had not been changed.

One man wanted by the police has been accused of "breaking police cordons" on Monday in the city's Economic and Technology Development Zone, according to one of the notices.

A separate notice issued by the Horqin district police via their official WeChat account sought information on 129 people for the same accusation of "picking quarrels and causing troubles."

The notices all promised cash rewards of 1,000 yuan (S$199) for anyone who provided reliable information on their identities.

Tongliao police also urged the people to surrender themselves.