Enlarge / Debris from the upper stage of China's Long March 6A rocket captured from the ground by Slingshot Aerospace. (credit: Slingshot Aerospace)

The upper stage from a Chinese rocket that launched a batch of Internet satellites Tuesday has broken apart in space, creating a debris field of at least 700 objects in one of the most heavily-trafficked zones in low-Earth orbit.

US Space Command, which tracks objects in orbit with a network of radars and optical sensors, confirmed the rocket breakup Thursday. Space Command initially said the event created more than 300 pieces of trackable debris. The military's ground-based radars are capable of tracking objects larger than 10 centimeters (4 inches).

Later Thursday, LeoLabs, a commercial space situational awareness company, said its radars detected at least 700 objects attributed to the Chinese rocket. The number of debris fragments could rise to more than 900, LeoLabs said.

Enlarge / A Long March 6A rocket launches the first 18 Internet satellites for China's Qianfan, or Thousand Sails, broadband network. (credit: VCG via Getty Images)

Chinese officials have long signaled their interest in deploying a satellite network, or maybe several, to beam broadband Internet signals across China and other nations within its sphere of influence.

Two serious efforts are underway in China to develop a rival to SpaceX's Starlink network, which the Chinese government has banned in its territory. The first batch of 18 satellites for one of those Chinese networks launched into low-Earth orbit Tuesday.

A Long March 6A rocket delivered the 18 spacecraft into a polar orbit following liftoff at 2:42 am EDT (06:42 UTC) from the Taiyuan launch base in northern China's Shanxi province. The Long March 6A is one of China's newest rockets—and the country's first to employ strap-on solid rocket boosters—with the ability to deploy a payload of up to 4.5 metric tons (9,900 pounds) into a 700-kilometer (435-mile) Sun-synchronous orbit.