China launched extensive military drills near Taiwan on Monday in what it called a “stern warning” against separatist and “external interference” forces after the Trump Administration announced an $11.1 billion arms sale to the island earlier this month.

The Chinese military’s “Justice Mission 2025” exercises—the first major drills it has held around the island since April—are to include combat-readiness and port-blockade drills, complete with live fire and simulated land and sea strikes, along seven zones across the island, in part to deter outside intervention, China’s Eastern Theater Command announced. 

Taiwan has been self-governed since 1949, after Nationalist forces fled to the island following their defeat by Chinese Communist powers. But China has maintained that it has sovereignty over Taiwan and long called for a “reunification” between the smaller territory and the People’s Republic of China. 

Senior Col. Shi Yi, spokesperson of the Eastern Theater Command, said the drills were a “stern warning against ‘Taiwan independence’ separatist forces and external interference forces” and described the military action as a “necessary” move to protect China’s "sovereignty and national unity.” 

Taiwan’s Defense Ministry, meanwhile, said the exercises “further confirm” the Chinese Communist Party’s “nature as an aggressor and the biggest destroyer of peace.” 

In the drills, China is operating dozens of aircraft and drones around the Taiwan Strait, according to the deputy chief of the general staff for intelligence for the Taiwanese Defense Ministry, Hsieh Jih-sheng. More than 100,000 travelers on international flights were set to be affected by the Chinese military’s actions, per the island’s Transport Ministry.  

Military drills are expected to continue through Tuesday, Taiwan’s Civil Aviation Administration said. 

Read more: How Trump Can Avoid a War Over Taiwan

The exercises come as China has expressed ire over the recent $11.1 billion U.S. arms sale to Taiwan, which includes high mobility artillery rocket systems (HIMARS) and harpoon missile repair related equipment. The U.S. previously approved more than $1 billion in arms sales to Taiwan in November. 

Last week, the Chinese foreign ministry enacted sanctions against 20 U.S. defense firms in the wake of the sales, barring companies such as Boeing from doing business with the global superpower. Ten executives for those companies were also barred from entering China or doing business in the country under the sanctions. 

The State Department notified Congress that it had approved the large-scale sale to Taiwan less than two weeks ago, saying that the potential deal “serves U.S. national, economic, and security interests by supporting the recipient's continuing efforts to modernize its armed forces and to maintain a credible defensive capability."