Schools, including kindergartens, primary and high schools, have suspended Monday classes in Manzhouli and Baotou, two cities in the Inner Mongolia autonomous region, due to the sweeping sandstorms.

In Baotou city, all outdoor events at kindergartens and schools have been ordered to cease on Monday.

In addition, the airport in Manzhouli has also been temporarily closed for safety reasons noon Monday, according to city authorities.

Relevant departments and rescue workers have been required to stand by 24 hours and prepare for a possible blackout in the city, authorities said.

The sandstorms also hit other cities in the Inner Mongolia and other provinces and regions in north and northeastern China, with visibility lowering within 1,000 meters, authorities said.

It has triggered many cities to issue high level warnings. For example, Hohhot, capital of Inner Mongolia, has upgraded to an orange alert for sandstorms, the second-highest in the three-tiered warning system.