BEIJING — A video showing an S.U.V. running over a toddler while her mother appeared distracted by her phone has prompted hand-wringing on Chinese social media about the perils of overusing smartphones.

Surveillance cameras captured a slow-moving S.U.V. hitting a 2-year-old girl who had veered into its path. Her mother, trailing behind on a street in a provincial Chinese city, had been glued to her phone and appeared not to notice that the vehicle had started moving. By the time an ambulance arrived, the girl had died.

In China, as in the United States and elsewhere, people are clicking, texting and shopping on their smartphones in droves, and many do so while on the move.

About 710 million people in China, or 92 percent of its internet users, go online via their smartphones, more than twice as many as in 2012, government data shows. About a quarter of those use only their smartphones.