LANZHOU, March 4 (Xinhua) -- A total of 146 Chinese citizens have been put under medical observation in a hospital in Lanzhou, northwest China's Gansu Province, after returning from Iran, local authorities said Wednesday.

The Chinese citizens aboard a China Southern Airlines flight landed at the Lanzhou Zhongchuan International Airport around 2 p.m. Gansu Province has set up a team for making medical observation plans and sent health workers from several hospitals to undertake relevant work.

They were put in separate rooms in the hospital, which has prepared nearly 500 beds, with independent toilets and basic utilities in each room.