BEIJING, Dec. 29 (Xinhua) -- China's defense ministry said on Monday that joint drills launched by the People's Liberation Army (PLA) Eastern Theater Command served as a stern warning to separatist forces advocating "Taiwan independence" and to external interference.

Zhang Xiaogang, a spokesperson for the Ministry of National Defense, made the remarks in response to media reports that the "Justice Mission 2025" drills were related to the recent U.S. announcement of a large arms sales plan to Taiwan.

"We urge relevant countries to abandon the illusion of using Taiwan to contain China, and to refrain from challenging China's resolve in safeguarding its core interests," Zhang said, who also warned Taiwan's Democratic Progressive Party authorities that any attempt to seek "Taiwan independence" by relying on external forces is doomed to fail.

The PLA will continue taking measures to fight secession and external interference to firmly safeguard China's national sovereignty, unity and territorial integrity, he added.