The United States is weighing a new operation to send warships through the Taiwan Strait, officials told Reuters early Saturday.

The operation, which would guarantee free passage through a key waterway, could ratchet up already high tensions with China, the outlet noted.

{mosads}The U.S. sent two warships through the strait in July as the ongoing trade dispute between the U.S. and China began.

China has claimed that Taiwan is part of its country, while Taiwan views itself as an independent nation. The U.S. does not acknowledge Taiwanese independence.

According to Reuters, China raised concerns over the U.S.’s relationship with Taiwan during talks with Defense Secretary James Mattis in Singapore this week. Chinese officials warned late last month that a State Department-approved sale of F-16 fighter jet spare parts to Taiwan would violate international law and damage U.S.-China relations.

U.S. Assistant Secretary of Defense Randall Schriver told Reuters that Mattis assured his Chinese counterpart that Washington’s stance on Taiwan remains unchanged.

“Minister Wei raised Taiwan and concerns about our policy,” he said. “The Secretary reassured Minister Wei that we haven’t changed our Taiwan policy, our one China policy.”

Tensions between the U.S. and China in the South China Sea have been on the rise in recent months.

Early this month, a Chinese warship had an “unsafe” interaction with a U.S. destroyer near disputed islands in the South China Sea, a Navy spokesman told The Hill.

In September, U.S. B-52 bombers flew over the South China Sea and East China Sea, according to U.S. military officials, who said the operations were routine and “designed to enhance our readiness and interoperability with our partners and allies in the region.”

The Defense Department declined to comment, citing security reasons. 

— Updated 9:15 p.m.