China's abstention from Wednesday's UN vote to condemn the Assad regime's chemical attack in Syria was due in part to the connection established between President Xi Jinping and President Trump last week, according to a senior White House official.

Echoing Trump's own comments during a press conference earlier Wednesday, the official said China's abstention was a "significant victory for all civilized peoples because it really showed how isolated … the Assad regime [is]."

The official declined to say whether Trump asked Xi to abstain from the vote when they spoke by phone Tuesday evening. Though the president's recent bilateral summit with his Chinese counterpart likely facilitated the abstention, the official said.

"The relationship was solidified at Mar-a-Lago that helped make that possible and help these two leaders work together based on common interest," the official said.

Trump and Xi had a "very warm conversation" Tuesday evening about their own meeting last week and their spouses' meeting, according to the White House.

"What I can say about the conversation is that it was a very frank and open about two very complicated problems," the official said, referring to the escalating conflict in Syria and nuclear ambitions of North Korea.

China has vetoed six UN resolutions related to Syria since the country's civil war began. The country's abstention on Wednesday put them in the same camp as Ethiopia and Kazakhstan. Russia was the only nation to vote no.