BEIJING -?China confirmed on Monday its Foreign Ministry has lodged solemn representations to the Democratic People's Republic of Korea (DPRK) embassy in Beijing over its sixth nuclear test.

"The representations were lodged to the person in charge of the embassy," Foreign Ministry spokesperson Geng Shuang said at a regular news briefing.

The DPRK Sunday detonated a hydrogen bomb that can be carried by an intercontinental ballistic missile (ICBM), DPRK's Central Television announced. This was the sixth nuclear test the DPRK has undertaken.

"China's adherence to denuclearizing the Korean Peninsula and opposition to nuclear tests and missile development by the DPRK is well-known," Geng said.

China has proposed realizing denuclearization on the Korean Peninsula while establishing a peace mechanism. China has also expected the DPRK to suspend its nuclear and missile activities in exchange for the suspension of large-scale U.S.-ROK military exercises.

Geng stressed that use of force is not an option for resolving the nuclear issue on the Korean Peninsula, expressing appreciation for a number of countries' calling for a peaceful settlement of the problem.

China's Ministry of Environmental Protection on Sunday started monitoring the radiation levels in the border areas in an emergency response to the nuclear test, and recorded radiation at normal levels.

"China will take necessary measures to protect the safety of citizens and the environment," the spokesperson said.