China sent more military aircraft into a sensitive area off Taiwan following a brief period that saw it mysteriously hold off on the flights.

Five People¡¯s Liberation Army (PLA) aircraft were detected in Taiwan¡¯s air defense identification zone ¡ª a space closely monitored by the military ¡ª from 6 a.m. Wednesday to 6 a.m. Thursday, the Defense Ministry in Taipei said in a statement.

Three of the planes crossed the median line in the strait, which serves as an unofficial boundary between Taiwan and China.

PLA flights around the ADIZ and the median line have fallen off lately for no clear reason. Taiwan said the pause may be a tactic by Beijing to ease tensions before an expected meeting between President Donald Trump and Chinese leader Xi Jinping in Beijing in a few weeks. The Trump administration was delaying a multi-billion dollar arms sale to Taiwan to ensure the visit was successful, the New York Times reported earlier.

The status of Taiwan is one of the thorniest issues in U.S.-China ties. Xi told Trump in a February phone call that Beijing would never allow Taiwan to be separated and warned the U.S. should handle arms sales to Taipei with the ¡°utmost caution.¡±

Taipei rejects Beijing¡¯s view that it is part of China, and in recent years has been working to improve its defenses to deter the PLA.

The recent slowdown in flights coincided with China holding a major meeting of lawmakers. And Tristan Tang, a nonresident fellow at the Pacific Forum, has said the absence of PLA aircraft aligned with a longer-term shift toward more joint operations training that began last year.

For years, China has used military aircraft buzzing around Taiwan as a pressure tactic, forcing the much smaller adversary to scramble jets in response. The recent pause was interrupted by two planes flying in Taiwan¡¯s ADIZ on March 6-7, and Chinese naval activity around Taiwan has continued through the period.

Separately, the U.S. Navy said in a statement that it sent a P-8A Poseidon reconnaissance aircraft through the Taiwan Strait on Wednesday, adding that this ¡°demonstrates the United States¡¯ commitment to a free and open Indo-Pacific.¡±

The Global Times, a Chinese media outlet, said the PLA monitored the flight.