Coronavirus tests imported from South Korea by the governor of the US state of Maryland were flawed and ended up not being used, The Washington Post reported on Friday.
The newspaper said Maryland Governor Larry Hogan spent $9.46 million in April to import 500,000 coronavirus tests from South Korea.
But the tests turned out to be flawed and the state "quietly" paid the same South Korean company an additional $2.5 million for 500,000 replacement tests, the Post said.
It said a University of Maryland laboratory abandoned its use of the replacement tests after a spate of suspected false positives but a private lab continues to use them.
Around 370,000 of the replacement tests have been used by the private lab, the Post said.
Hogan, a frequent critic of President Donald Trump, trumpeted the arrival of the South Korea tests in April and praised the assistance of his South Korean-born wife in obtaining them.
Hogan declined requests to comment on the newspaper's story, the Post said.