"If at the end of this period of time, the parties are unable to reach an agreement, the 10% tariffs will be raised to 25%", she said.
The Trump-Xi meeting is set to be the marquee event of Trump's whirlwind two-day trip to Argentina for the Group of 20 Summit after the president cancelled a sit-down with Russian President Vladimir Putin over mounting tensions between Russia and Ukraine.
Trump himself said Bush had "inspired generations of his fellow Americans to public service".
"Facts have proven that China and the US have more common interests than differences, and have greater need for cooperation than friction".
Trump told Xi at the start of the meeting he hoped they would achieve "something great" on trade for both countries.
In a sign of what the trade thaw may mean for global market confidence, the American S&P 500 was up 4.14 per cent last week in anticipation of the meeting.
"Climate change presents numerous challenges to sustaining and enhancing crop productivity, livestock health, and the economic vitality of rural communities", the report reads, adding that water supplies in the US could also be impacted by climate change.
"We're working very hard".
According to European officials, the United States negotiator said too much talk about migration would have been a "deal-breaker" for Mr Trump.
"I think across the board it was really a resounding success".
The declaration struck a neutral formula on trade, reading: "We welcome the strong global economic growth while recognizing it has been increasingly less synchronized between countries and some of the key risks, including financial vulnerabilities and geopolitical concerns, have partially materialized".
Tito Ortiz crushes Chuck Liddell in first round knockout, video
The 48-year-old Liddell last competed in June of 2010, when he suffered a knocked out loss at the hands of Rich Franklin. After some initial exchanges, the confidence of Ortiz grew and he put Chuck away near the end of the first round.
Earlier in the day, the G20 leaders agreed to reform the World Trade Organisation, a big win for Trump who has heavily critisised it.
Argentine President Mauricio Macri, the summit's host, said at a news conference following the gathering that the United States did not accept a proposal by its G20 counterparts to refer to "fighting protectionism" in the communique.
"The United States has no proof that most fentanyl in the country comes from China", he said. "It was the weakest communique we've ever seen from the G20", he told AFP, contrasting the group's posture now in the Trump era to its sense of common goal when the leaders first met 10 years ago in the midst of a financial crisis. China calls the United States protectionist and has resisted what it views as attempts to intimidate it.
"Should there be any other aspirations, such as taking advantage of the trade spat to throttle Chinese growth, then an agreement is unlikely to be reached", the newspaper said in an editorial Friday. If we could make a deal that would be good. "We will review progress at our next summit", it said.
"It goes down, certainly - if it happens, it goes down as one of the largest deals ever made", Trump told reporters aboard Air Force One as he returned from Argentina.
While short of the complete rewrite of NAFTA once promised by Trump, he hailed the new United States-Mexico-Canada-Agreement as an "incredible milestone".
So far, China's actions in this regard have been fully recognized by the global community including the United States.
With Trump feuding with close United States allies, not least on climate change, two major summits this year ended without once-routine statements - those of the Group of Seven democracies and the Asia-Pacific Economic Cooperation forum.
Trump has made a decision to pull the United States from the Paris accord on curbing carbon emissions, saying it is unfair, despite mounting evidence of the changing climate's dire effects.
While a statement is not legally enforceable, the Europeans see it as proof the G20 is still relevant and multilateralism still works. He struck a positive note as he sat across from Xi, despite the USA president's earlier threats to impose new tariffs on Chinese imports as early as the start of next year.