A senior U.S. diplomat handling missile defense issues is set to visit China this week for a regional security meeting and bilateral discussions, the State Department said, amid speculation his meetings with Chinese officials could include the THAAD missile defense system.

Frank Rose, assistant secretary of state for arms control, verification and compliance, will visit Beijing from Monday through Thursday to attend an ASEAN Regional Forum workshop on space security, the department said in a release.

"Additionally, he will meet with senior officials from the Ministry of Foreign Affairs to discuss issues of mutual concern," the department said.

The department did not elaborate on the topics for Rose's discussions with Chinese officials, but the Terminal High Altitude Area Defense missile defense system is considered one of the issues of mutual concern between the two countries.

The U.S. wants to deploy a THAAD missile interceptor battery to South Korea, where some 28,500 American troops are stationed, to better defend against ever-growing threats from North Korea's ballistic missile and nuclear programs.

China has expressed strong opposition to a THAAD placement in South Korea as it sees such a deployment as a threat to security interests. Beijing has openly pressured South Korea to reject any U.S. request for a deployment.

Rose, a main State Department official handling missile defense issues, said in May that the U.S. is considering permanently stationing a THAAD missile defense unit in South Korea to help defend against North Korean threats.

Rose also said that THAAD is a purely defensive system that cannot impact broader strategic stability with Russia or China. He went on to claim that Beijing's opposition to THAAD could be an attempt to "create a wedge in the U.S. alliance system in the region."

South Korea and the U.S. have maintained that they've never held formal consultations on THAAD. (Yonhap)