The US reduced its number of naval transits through the Taiwan Strait in 2022 to the lowest level in four years even as China stepped up military pressure on the island, Bloomberg reported.

The US 7th Fleet sent nine warships through the body of water separating China and Taiwan last year, according to Bloomberg-compiled data. The fleet did say it sailed a destroyer though on Thursday, one the Chinese military said it monitored.

The US Navy also conducted four “freedom-of-navigation operations” through the South China Sea, the fewest in six years, trips it says show its dedication to a “free and open Indo-Pacific.”

The decline in US naval activity contrasts with the roughly 1,700 warplanes that China sent into Taiwan’s sensitive air-defense identification zone last year, nearly double the number of 2021.

The shift by the US also comes as ties with China have improved since a meeting in November between Chinese leader Xi Jinping and President Joe Biden at the Group of 20 summit in Indonesia. 

Reducing the number of voyages through the strait or the South China Sea—where several nations and Taiwan have territorial disputes with China—would be a way for the US to eliminate some friction.

China’s Foreign Ministry spokesman Wang Wenbin last month called US military activity near its shores “provocative and dangerous.”

Last year, Chinese military officials reportedly told their US counterparts that the Taiwan Strait isn’t international waters, and Wang later said China had “sovereignty” over the area.

The US sent two guided-missile cruisers through the Taiwan Strait just after China held major military exercises in August to show its displeasure over then-House Speaker Nancy Pelosi’s trip to Taipei.

The US’s move may have been a calibrated signal by the Biden administration to show it was resolved to maintain a naval presence in the waterway without prompting an additional response from China.