The Trump administration plans to make an announcement next week related to escalating tensions in the South China Sea, where Washington and Beijing are vying for military supremacy, according to two people familiar with the matter.

The U.S. has raised concerns over China’s decision to conduct military exercises in the contested waters around the Paracel Islands. The Defense Department last week called the actions "unlawful,” and the U.S. plans to lay out its official position next week, said one of the people who spoke on condition of anonymity.

The unspecified move comes as President Donald Trump has intensified his criticism of Beijing over issues from the coronavirus pandemic to trade. A spokesperson for the National Security Council didn’t immediately respond to a request for comment.

Stretching from China in the north to Indonesia in the south, the South China Sea encompasses 1.4 million square miles (3.6 million square kilometers). China claims more than 80 percent of the South China Sea and backs up its claim with a 1947 map that shows vague dashes — what became known as the "nine-dash line." Vietnam, the Philippines, Brunei, Malaysia and Taiwan claim parts of the same maritime area.

Beijing has rejected claims that it’s doing anything out of the ordinary in the South China Sea and has indirectly accused the U.S. of trying to sow discord between China and Southeast Asian nations.