WASHINGTON - Federal officials will require all international travelers flying to the United States to show proof they have tested negative for the coronavirus, Centers for Disease Control and Prevention officials announced Tuesday.

As Maryland Gov. Larry Hogan negotiated receipt of 500,000 coronavirus tests from South Korea this spring, a domestic test distributor tried to sell the state a million or more federally authorized tests at less than two-thirds the price, according to emails between the distributor and a state health official.