China is holding military drills around Taiwan simulating a blockade of key ports and areas, in what it calls a warning to “separatist forces” in Taiwan.

The army, navy, air force and rocket force troops have been dispatched for the drills, the Chinese military said.

The People’s Liberation Army (PLA) said the eastern theater command had sent forces to conduct drills in the Taiwan Strait and areas to the north, southwest, southeast and east of Taiwan Island.

The exercise around Taiwan Island on Monday, code-named Justice Mission 2025, was a stern warning against separatist forces and external interference, and a legitimate and necessary action to safeguard China’s sovereignty and national unity, said a spokesperson for the PLA’s eastern theater command Shi Yi.

“With vessels and aircraft approaching Taiwan Island in close proximity from different directions, troops of multiple services engage in joint assaults to test their joint operations capabilities,” he added.

In a statement announcing the drills, China’s eastern theater command said: “On December 29, the PLA eastern theater command employed destroyers, frigates, fighters and bombers to conduct drills in the waters and airspace to the east of the Taiwan Strait, focusing on subjects of assault on maritime targets, seizure of regional air superiority as well as submarine hunting and anti-submarine operations. The drills tested capabilities of sea-air coordination and of precise target hunting and neutralization.”

The PLA eastern theater command is also employing destroyers, frigates, fighters, bombers and unmanned aerial vehicles in coordination with long-range rocket fires to conduct training in the waters and airspace to the north and southwest of the Taiwan Strait.

The training focuses on subjects of hunting and neutralizing targets in waters and airspace, simulated strikes on ground targets, and live firing against targets in waters.

The PLA eastern theater command noted the drills intend to test the troops’ capabilities of integrated coordination and seizure of dominance.

Beijing’s foreign ministry spokesperson Lin Jian urged on Friday the U.S. to “stop the dangerous moves of arming Taiwan,” and to stop sending wrong signals to “separatist forces.”

China’s foreign ministry expressed anger, as it does with all US arms sales to Taiwan, saying it “undermines peace and stability in the Taiwan Strait” and demanded an end to such deals.

“Any company or individual who engages in arms sales to Taiwan will pay the price for the wrongdoing,” the spokesperson warned.

Lin Jian told reporters on Monday in response to a question about the $11.1bn arms sales to Taiwan announced by the U.S. that “anyone who tries to arm Taiwan to contain China will only embolden the separatists and push the Taiwan Strait closer to the peril of armed conflict.”

Taiwan’s defence ministry said they detected PLA aircraft and ships around Taiwan on Monday morning, and have deployed their forces to monitor the situation.