The destroyer "approached within 45 yards of Decatur's bow, after which Decatur maneuvered to prevent a collision", he said.
But according to the USA, the Chinese Luyang destroyer approached the Decatur in "an unsafe and unprofessional maneuver" that required evasive actions.
Over the last week, the USA and Chinese military relationship has deteriorated as both countries are engaged in a bitter trade dispute.
Beijing claims all of the Spratlys and has built a number of military installations on the islands.
The Chinese ship then conducted a series of 'increasingly aggressive maneuvers, and warned the Decatur to depart the area, ' he added.
The close encounter with the Chinese warship occurred as the American destroyer was carrying out a freedom of navigation operation (FONOPs) in the Spratlys, the us said.
While Beijing repeatedly claimed the right to protect its interests and territorial claims in the South China Sea and slammed the abuse of the "freedom of navigation" principle, the Pacific Fleet vowed to continue sailing close to disputed waters.
Which brings us to an ABC News report published Monday evening detailing just how close Chinese ships came to actively confronting the USS Decatur while the U.S. ship was carrying out yet another in a series of "freedom of navigation" operations - or "freeops" - in the South China Sea. Twelve nautical miles is the commonly accepted limit for territorial waters.
Real Madrid vs. Atletico Madrid - Football Match Report
It was Julen Lopetegui's first derby as Real coach, although he was the fifth Real manager Diego Simeone had stood opposite. They're experts at keeping clean sheets thanks to the experience, leadership and defensive nous they have across the team.
The US routinely angers Beijing with "freedom of navigation" missions. In addition, they were "seriously undermining the relations between the two countries and the two armed forces, and seriously endangering regional peace and stability", it said.
China's Foreign Ministry said in a separate statement it strongly urged the United States to stop such "provocative" actions and to "immediately correct its mistakes".
President Donald Trump ordered new levies on $200 billion in Chinese imports, and Beijing responded with tariffs on $60 billion in American products, nearing the point of running out of US goods to target.
On Monday, a USA official confirmed that Defense Secretary Jim Mattis had canceled a planned trip to China in October after China had downgraded the level of officials he was to meet.
The incident comes amid rising tensions between the naval powers.
Washington last week enacted new tariffs against China covering another $200 billion of its imports. The American ship changed course to prevent a collision, Brown said.
Beijing last month refused a USA warship entry to Hong Kong, and its top naval officer canceled a high-level meeting with his US counterpart.
The maritime showdown came about a week after Chinese officials canceled military talks with the United States that were supposed to be held in Beijing in late September.
China has not yet commented on the matter.