WASHINGTON (Reuters) - U.S. Democratic presidential candidate Hillary Clinton said in a private speech to bankers three years ago that the United States had warned Beijing it would “ring China with missile defense” unless it did more to rein in North Korea’s missile program, according to hacked emails.

U.S. Democratic presidential nominee Hillary Clinton speaks at a rally at the Colorado State Fair Grounds in Pueblo, Colorado, U.S. October 12, 2016. REUTERS/Lucy Nicholson

According to a purported Clinton campaign document attached to an email published by Wikileaks, Clinton said in a speech to Goldman Sachs on June 4, 2013, that the message to China had been, “You either control them, or we’re going to have to defend against them.”

It was not possible to confirm the authenticity of the leaked email. The Clinton campaign has neither confirmed nor denied the authenticity of hacked emails.

The State Department on Friday declined to comment on “alleged leaked documents.” When asked whether such a message had been delivered to China, an official said it was not department policy to comment publicly on diplomatic discussions.

Although Clinton’s reported comments raised a stir in Asia, they are consistent with U.S. efforts to convince China to help restrain North Korea’s nuclear and ballistic missile programs, which so far have borne little fruit.

According to the hacked email, Clinton said in the speech, which was delivered after she left her position as secretary of state, that Washington could not accept a situation in which North Korea developed an inter-continental ballistic missile able to carry a miniaturized warhead.

She said this not only could threaten treaty allies Japan and South Korea, but also theoretically could reach Hawaii and the West Coast of the United States.

“We’re going to ring China with missile defense. We’re going to put more of our fleet in the area,” Clinton said, according to the email. “So China, come on. You either control them, or we’re going to have to defend against them.”

China has been angered by plans announced this year by the United States and South Korea to deploy the U.S. Terminal High Altitude Area Defense (THAAD) anti-missile system to protect against the threat posed by North Korean missiles.

The United States has argued THAAD is not aimed at containing China, but Beijing is concerned that the system’s powerful radar would compromise its security.

Current U.S. Secretary of State John Kerry said in February that the United States had made clear that the way to prevent THAAD deployment was to resolve the North Korean nuclear issue.

According to the leaked emails and in other paid speeches, Clinton also praised Chinese leader President Xi Jinping as a “more worldly, somewhat more experienced” politician than his predecessor Hu Jintao, and one who had worked to assert his authority over the People’s Liberation Army.

Clinton said she also told her Chinese counterparts that the United States had as much a claim to the Pacific as China, given that U.S. forces had liberated it in World War Two.

China had “a right to assert themselves,” but the United States needed to “push back to create a balance” to prevent China taking a chokehold on sea lanes and countries bordering the South China Sea, she said.