Washington: US President Donald Trump said he forged a friendship with Chinese counterpart Xi Jinping, striking a positive tone in the early hours of the first-ever meeting between leaders of the world's two biggest economies.

"We had a long discussion already and so far I have gotten nothing, absolutely nothing," Trump joked on Thursday night at his Mar-a-Lago resort in Florida while dining with Xi, who arrived in the afternoon. "But we have developed a friendship. I can see that."

"I think, long-term, we are going to have a very, very great relationship and I look very much forward to it," Trump said.

The remarks came shortly before the US launched a cruise missile strike against Syria after Bashar al-Assad's regime used poison gas to kill scores of children. Trump had ignored a shouted question about Syria while he met with Xi.