WASHINGTON - U.S. Trade Representative Robert E. Lighthizer said he expects China to fulfill its promise to buy an additional $200 billion in American goods and services over the next two years, despite its slow start to placing new orders amid the coronavirus pandemic.

The trade agreement President Donald Trump signed with China less than four months ago has gone from a cornerstone of his re-election bid to a potential political liability as the pandemic sours the relationship between the world's two biggest economies.