A Chinese rocket has broken up in low-Earth orbit, creating a cloud of space debris, according to the U.S. Space Command.

(CNN) – One of China's Long March 6A rockets has broken up in low-Earth orbit, creating a cloud of debris consisting of hundreds of pieces, according to multiple space debris tracking entities.

The rocket took off on Tuesday from the Taiyuan Satellite Launch Center to launch 18 G60 satellites, marking the first deployment of Shanghai Spacecom Satellite Technology Group's Thousand Sails constellation.

The mega satellite constellation will eventually include 1,296 satellites, with plans to expand capacity to about 14,000 to rival SpaceX’s Starlink satellites.

Shanghai Spacecom Satellite Technology did not respond to CNN's request for comment. The US Space Command (USSPACECOM), a branch of the US Department of Defense, confirmed the rocket breakup on Thursday.

“USSPACECOM has not observed any immediate threats and continues to conduct routine joint assessments to support the security and sustainability of the space domain,” according to a command spokesperson.

U.S. Space Command continues to track debris and provide information to NASA.

“There is no immediate threat to the International Space Station as a result of this breakup,” said Rob Margetta, NASA Headquarters public affairs officer.

The amount of debris tracked changed hourly Thursday, starting with more than 50 tracked by Slingshot Aerospace's Global Sensor Network. Later, U.S. Space Command said it was tracking more than 300 pieces.

Now, radar data from tracking organization LeoLabs has confirmed that the event produced at least 700 pieces of debris and potentially more than 900.

The rocket is believed to have broken up 500 miles (810 kilometers) above the Earth's surface, and the debris poses “a significant hazard to (low-Earth orbit) constellations” below 500 miles (800 kilometers) altitude, according to Slingshot.

For reference, the International Space Station orbits about 408 kilometers above Earth.

Slingshot’s Horus sensor systems, which track satellites in low Earth orbit, “detected a number of unexpected bright objects traveling along the same orbital path as the rocket body and the G60 satellites it was deploying.”

The true risks from the debris cloud won't be known until experts have a chance to fully analyze it, which could take another day or so. And the reason for the rocket's breakup remains unknown.

Because the Chinese satellites were put into orbit around Earth’s poles, rather than an equatorial orbit, “they will have a real impact with other objects that are not in polar orbit,” such as two vehicles colliding at an intersection, said John L. Crassidis, the Moog Professor of Innovation in the University at Buffalo’s College of Engineering and Applied Science.

Everything in low Earth orbit travels at 17,500 miles per hour, Crassidis said.

“In the worst case, any part of the debris field would hit something moving around the equator,” he explains. “That’s the case for a T-intersection. Imagine two cars going 17,000 miles per hour and they collide at a T-intersection. Obviously, that’s bad. In general, any object in their path is still a bad situation.”

Given the altitude at which the breakup occurred, the debris is likely to remain in place for several years, and some could remain for decades, but it's difficult to predict how long without knowing the shapes of the debris, Crassidis said.

It is the second time one of these rocket bodies has experienced a significant breakup in low-Earth orbit, according to Victoria Heath, associate director of marketing and communications at LeoLabs.

Another Long March 6A rocket body exploded in a region of low-Earth orbit densely populated by satellites on Nov. 12, 2022, with the resulting 500-plus debris fragments spread over 320 to 1,500 kilometers and increasing the risk of collision with satellites, especially in the center of the debris cloud, according to LeoLabs.

The company carried out a analysis and concluded that the November 2022 event was triggered by a problem related to the spacecraft's propulsion system, rather than fragmentation due to the rocket colliding with another object.

According to LeoLabs, there are currently about 1,000 abandoned rocket bodies in low Earth orbit, and that figure continues to rise due to increased launches as more countries focus on their space ambitions.

“If even a fraction of the launches needed to get this Chinese mega-constellation up and running generates as much debris as this first launch, the result would be a notable addition to the space debris population in (low Earth orbit),” said Audrey Schaffer, vice president of strategy and policy for Slingshot Aerospace. in a statement.

“Events such as this highlight the importance of adhering to existing space debris mitigation guidelines to reduce the creation of new space debris and underscore the need for robust space domain awareness capabilities to rapidly detect, track and catalog newly launched space objects so they can be examined for potential conjunctions.”