U.S. Sen. John McCain, the Republican head of the Senate Armed Services Committee, has urged the Pentagon to clarify publicly the legal intent of a U.S. patrol last month that went within 12 nautical miles of a disputed island China has built in the South China Sea, Reuters reported Wednesday. Chinese officials had called the move “provocative” and “dangerous.”

“I believe it is critical that the Department of Defense publicly clarify, to the greatest extent possible, the legal intent behind this operation and any future operations of a similar nature,” McCain wrote in a letter to Defense Secretary Ashton Carter, published by the U.S. Naval Institute News.  

China has claimed the majority of the South China Sea. International maritime law states that a nation can claim water extending 12 nautical miles from its coasts as sovereign territory. U.S. officials said last week that the U.S. Navy avoided military drills that could have aggravated tensions with Beijing during the patrol by the destroyer last month, which tactic experts said could reinforce rather than challenge China's sovereignty claims, according to Reuters. If the destroyer did not conduct military drills, the passage would have reportedly resembled an “innocent passage.” Pentagon officials have given mixed descriptions regarding last month’s operation. 

GettyImages-494457140 U.S. John McCain, R-Ariz. (right), and Sen. James Inhofe, R-Okla., of the Senate Armed Services Committee, hold a hearing about U.S. military strategy on Capitol Hill, Oct. 27, 2015. Photo: Getty Images

“I don’t like in general the idea of talking about our military operations,” Carter told the Senate Armed Services Committee the day after the operation following repeated questioning, the Hill reported. “But what you read in the newspaper is accurate.”

McCain called for the Pentagon to detail the territorial claims the Navy is challenging, under what authority the ship sailed through the waters, and whether China was notified ahead of time, according to the Hill.

“Given the sensitive political dynamics and detailed legal implications of our actions,” McCain wrote. “It is vital that there be no misunderstanding about our objectives in either the Asia-Pacific region or within the international community.” 

The Pentagon has yet to respond to McCain’s letter.