China's economy already has shown signs of slowing, while the trade war has shaken the confidence of U.S. businesses, as retaliatory tariffs have raised prices and helped choke off a key export market.
USA tariffs on $200 billion (155 billion pounds) worth of imports from China are scheduled to rise to 25 percent from 10 percent if the two sides can not reach a deal by a March 1 deadline, increasing pain and costs in sectors from consumer electronics to agriculture.
"We're doing very well over in China", Trump added.
"I think they're making progress and my hope is that by March 1 there will be enough progress to be made that at a minimum, there could be a delay in the imposition of additional tariffs", Portman told reporters.
U.S. Treasury Secretary Steven Mnuchin, a member of the U.S. trade delegation to China, leaves a hotel in Beijing, China February 13, 2019.
Mnuchin, along with U.S. Trade Representative Robert Lighthizer, arrived in the Chinese capital on Tuesday.
Washington is expected to keep pressing Beijing on long-standing demands that it make sweeping structural reforms to protect American companies' intellectual property, end policies aimed at forcing the transfer of technology to Chinese companies, and curb industrial subsidies.
U.S. President Donald Trump said he's open to extending a March 1 deadline to raise tariffs on Chinese products if the two sides are near an agreement.
Trump said talks in Beijing are "going well", but acknowledged bilateral talks between him and Xi are unlikely to come to pass before the current March 2 deadline. A round of talks at the end of January ended with some progress reported, but no deal and USA declarations that much more work was needed.
Lower level officials had arrived earlier for what the White House has called preparatory meetings due to start on Monday. According to a White House official, the delegates were preparing to focus more on pressing Beijing to gain a structural reform in China's business policy for the United States firms.