The Chinese military launched drills around Taiwan on Saturday as a “stern warning” over what it called collusion between “separatists and foreign forces,” its defense ministry said, days after the island’s vice president stopped over in the United States.

Taiwanese Vice President William Lai’s recent trip to Paraguay to reinforce relations with his government’s last diplomatic partner in South America included stops in San Francisco and New York City. The mainland’s ruling Communist Party claims democratic Taiwan as part of its territory and says it has no right to conduct foreign relations.

A spokesperson for China’s Eastern Theater Command said in a brief statement that the military exercises involved the coordination of vessels and planes and their ability to seize control of air and sea spaces.

It was also testing the forces' “actual combat capabilities,” Shi Yi said. The drills were a warning over provocations from pro-Taiwan independence forces and foreign forces, he added.

The command released footage of the drills online that showed soldiers running, as well as military boats and planes.

State media CCTV reported that missile-equipped boats and fighter jets were involved in the operation and that units worked together to simulate the surrounding of Taiwan.

Taiwan’s defense ministry strongly condemned what it called “irrational, provocative moves” in a statement. It said it would deploy appropriate forces to respond to the drills and take action to “safeguard freedom and democracy.”

It said its military would stand ready in the face of the threats posted by the Chinese army, adding that its forces have “the ability, determination and confidence to safeguard national security.”

It posted a video on Facebook that showed previous military drills and said the Chinese military exercises reflected a militaristic mentality.

Taiwan and China split in 1949 following a civil war that ended with the ruling Communist Party in control of the mainland. The self-ruled island has never been part of the People’s Republic of China, but Beijing sees Taiwan as a breakaway province to be retaken by force if necessary.

China’s official Xinhua news agency on Saturday reported that an unnamed official in China’s Taiwan Work Office strongly condemned what it called further collusion between Taiwan’s ruling Democratic Progressive Party and the US and said it was a “new provocative move.”

The official pointed to the stopovers in the US, an interview Lai gave to news outlet Bloomberg and his meeting with US officials in Paraguay, the report said.