Baidu Inc's revenue stands to take a hit amid a standoff between the company, which is China's dominant search-engine operator, and a key advertiser - the nation's largest group of private hospitals.

The Putian (China) Health Industry Chamber of Commerce, an association of 8,500 private hospitals, urged its members to stop advertising on Baidu starting last weekend. The move followed Baidu's crackdown on what it said was false healthcare information in ads posted on its site.

The Beijing-based Baidu said in late March that it rejected ad requests last year from more than 7,800 hospitals affiliated with the Putian association.