The signing of a contract which would determine the location of a U.S. missile defence system in South Korea could be delayed, Seoul’s defence ministry said on Monday, according to the Yonhap News Agency.

South Korea and the U.S. say the deployment of the Terminal High Altitude Area Defence (THAAD) system is designed to protect against North Korea’s growing nuclear and ballistic capabilities.

But Beijing objects strongly to the use of THAAD in South Korea, where it says its powerful radar could penetrate Chinese territory, leading to calls from some South Korea opposition leaders to delay or cancel its deployment.

Former United Nations Secretary-General Ban Ki-moon, who is expected to run for president of South Korea, said on Sunday it is appropriate for THAAD to be deployed in the country.