China said it is “gravely concerned” by President Trump’s plan for the U.S. to build a multibillion-dollar Golden Dome missile defense shield and is encouraging Washington to halt its development.

Chinese Foreign Ministry spokesperson Mao Ning said Wednesday that the defense system, which Trump said would take $175 billion to build, will “exacerbate the risk of turning outer space into a battlefield,” therefore starting an arms race and shake up the international security and arms control “system.”

“The U.S., by putting itself first and being obsessed with pursuing absolute security, violates the principal diminish the security for all undermines global strategic balance and stability,” Mao said during a press conference.

“China is gravely concerned about this,” he continued. “We urge the U.S. to give up developing and deploying the global antimissile system at an early date and take concrete actions to enhance strategic mutual trust between countries and safeguard global strategic stability.”

Trump announced Tuesday that the missile system will be “fully operational” in less than three years and that the push will be led by Vice Chief of Space Operations Space Force Gen. Michael Guetlein. Canada will also be included in the effort.

“This design for the Golden Dome will integrate with our existing defense capabilities and should be fully operational before the end of my term,” the president said Tuesday during an announcement alongside Defense Secretary Pete Hegseth. “So, we’ll have it done in about three years.”

He added, “Once fully constructed, Golden Dome will be capable of intercepting missiles even if they are launched from other sides of the world, and even if they are launched from space, and we will have the best system ever built.”

The commander in chief said Alaska, Florida, Georgia and Indiana will be involved in the major defense project.