The Chinese military says it has launched two days of military drills surrounding Taiwan.
Beijing says they are "punishment" for what it calls "separatist acts" in Taiwan, coming just days after the new Taiwanese president took office.
China's Eastern Theater Command posted video of the exercises on social media on Thursday, appearing to show naval forces readying for mock combat.
Meanwhile, Taiwan released footage from a patrol boat, purported to show an encounter with a Chinese frigate.
The incident reportedly happened near Taiwan's remote islands.
China's military has released a map of the drills, showing areas marked in red surrounding Taiwan.
Beijing says the exercise will take place on Thursday and Friday, adding that troops will continue to practice attacks and other maneuvers at sea and on land.
Japan's Ishigaki Island is close to Taiwan.
Residents there say the drills are cause for concern.
Tensions have risen after Taiwanese President Lai Ching-te delivered an inaugural speech, in which he suggested he will not accept the one-China principle.
That prompted a strong response from Beijing.
China's Foreign Ministry spokesperson said, "Forces seeking Taiwan's independence will encounter difficulties in the face of the historical trend toward China's complete unification."
The drills coincided with an already-scheduled meeting between President Lai and Taiwanese marines.
Lai said, "Even though Taiwan faces challenges and external threats, we will continue to protect the values of freedom and democracy, as well as peace and stability in the region."
Lai did not comment on Beijing's exercises during the visit.
China's military has been putting pressure on Taiwan by conducting drills in the region.
But according to Ohara Bonji, a Senior Fellow at Sasakawa Peace Foundation, Beijing has made clear the latest exercises are not overly complicated, and will not involve the use of live ammunition.
The expert says, "Beijing may feel compelled to punish Taiwan, without excessively raising tensions with the US and Japan."
China carried out major exercises in 2022 in response to then-US House Speaker Nancy Pelosi's trip to Taiwan.
During those drills, Chinese forces fired ballistic missiles toward the waters near Taiwan, with some landing inside Japan's exclusive economic zone.