TAIPEI, Taiwan (AP) — China sent 14 warships, seven military aircraft and four balloons near Taiwan between Saturday and Sunday, according to Taiwan’s Defense Ministry, as Beijing ramps up pressure on the island it claims as its own.

China’s military activities come amid speculation Beijing might organize military drills around the island in response to Taiwanese President Lai Ching-te’s recent visit to Pacific allies, including U.S. stops in Hawaii and Guam.

China claims Taiwan, a self-ruled democracy of 23 million people, as its own territory, and bristles at other countries’ formal exchanges with Taiwan. The United States, like most countries, doesn’t recognize Taiwan as a country but is its main unofficial backer and sells it arms.

The Chinese government has pledged to annex Taiwan, through military force if necessary, and sends ships and military planes near the island almost daily.

The 14 warships, seven military planes and four balloons were reported over 24 hours between 6 a.m. on Saturday and 6 a.m. on Sunday, according to Taiwan’s Defense Ministry. The ministry said six of the aircraft crossed the median line of the Taiwan Strait, an unofficial demarcation zone between Taiwan and China.

One of the balloons brushed over the island’s northern tip, according to the ministry.

Lai on Friday called on China to refrain from threats and said Beijing’s military exercises “will not be able to win the respect” of neighboring countries.

Lai’s first overseas trip since taking office in May included visits to the Marshall Islands, Tuvalu and Palau, three of the 12 countries that have diplomatic ties with Taiwan. The rest of the world, including the U.S., has official ties with China.

Lai’s stops in Hawaii and Guam — from where he had phone calls with U.S. Congress leaders — angered China, which opposes U.S. arms sales and military assistance to Taiwan.

There was widespread speculation China might organize war games around Taiwan in response to the visit, though it was unclear when they might start.

In October, China held drills around Taiwan involving a record one-day total of 153 aircraft, 14 navy vessels and 12 Chinese government ships in response to a Lai speech in which he rejected Beijing’s claims over Taiwan.

Beijing has labeled Lai a separatist and refuses to speak to him.