US President Donald Trump has invited his Chinese counterpart Xi Jinping to sign the phase one of a bilateral trade deal when it is agreed upon, according to a top White House official. “President Trump has invited President Xi to the US if we are able to get that deal to sign phase one trade agreement, we'll have to see if that comes to pass or not. I am optimistic about it, I may actually say I'm cautiously optimistic about it,” US National Security Advisor Robert O’Brien said. Meanwhile, China is seeking the roll back of US tariffs on as