Left: Russian President Vladimir Putin attends his annual news conference in Moscow, Russia, Dec. 23, 2016. (Xinhua/Bai Xueqi)

Right: U.S. President Donald Trump speaks before signing a new legislation at the White House in Washington D.C., the United States, on June 23, 2017. (Xinhua/Ting Shen)

WASHINGTON, July 18 (Xinhua) -- The White House confirmed on Tuesday that U.S. President Donald Trump had a second, previously undisclosed conversation with his Russian counterpart Vladimir Putin during the G20 summit in Hamburg, Germany.

"There was a couples-only social dinner at the G20," U.S. National Security Council spokesman Michael Anton told ABC news. "Toward the end, the president spoke to Putin at the dinner."

Anton did not mention the length of the conversation, but multiple U.S. media, including the New York Times and CNN, on Tuesday cited a senior White House official as saying that the conversation lasted for nearly an hour.

In a series of tweets on Tuesday night, Trump blasted the news reports of his second conversation with Putin as "sick."

"Fake news story of secret dinner with Putin is 'sick.' All G20 leaders, and spouses, were invited by the Chancellor of Germany. Press knew!" Trump wrote.

Trump and Putin met face-to-face for the first time on July 7 on the sidelines of the G20 summit in Hamburg, Germany.