Baidu Inc warned that curbs on online advertising will hurt revenue growth for the next two to three quarters, delivering the latest dose of bad news to investors in China's largest internet search service.

The company forecast lower-than-expected sales of 18.04 billion yuan ($2.7 billion) to 18.58 billion yuan this quarter, hit by government limits on the amount of ads it can show users.

The bottom of that range translates to a decline of 1.9 percent, which would be the first drop at the search giant founded by Robin Li since at least 2007.