The US has purchased 750,000 coronavirus tests from South Korea, a country where early and aggressive testing proved effective at keeping the virus at bay.

The Federal Emergency Management Agency (FEMA) said it awarded contracts to South Korean manufacturers last week to provide approximately 750,000 tests, with the first shipment of 150,000 already delivered.

The next shipment of tests is expected to arrive on Wednesday. The tests were produced by South Korean companies SD Biosensor and Osang Healthcare. FEMA will pay $5.2 million to the former company and $3 million to the latter.

President Donald Trump has at times both praised and downplayed South Korea's comprehensive testing programme, which stands in contrast to the US response.

In March, Mr Trump praised South Korea's successes, but the following month claimed that US tests were more efficient and accurate than those in South Korea.

Data from South Korea suggests that 1 in every 142 South Koreans has received a coronavirus test. The US has tested one in every 786 Americans.

South Korea is experiencing a decline in cases thanks to its aggressive testing and efforts to trace the likely spread of infection.

Eventually, Mr Trump claimed the US was doing more testing "by far" than any other nation, including South Korea.

"Just reported that the United States has done far more 'testing' than any other nation, by far! In fact, over an eight day span, the United States now does more testing than what South Korea (which has been a very successful tester) does over an eight week span," Mr Trump tweeted.

While it was true that the US has tested more overall cases, it tested fewer people per capita, and generally only individuals who have exhibited symptoms, which only catches a portion of the people who may be actively spreading the virus.

"Yes, it's true that South Korea has run less tests as an absolute number. However, it is important to point out the huge difference in the population sizes," Aubree Gordon, associate professor of epidemiology at the University of Michigan said to CNN.

Jennifer Horney, director of the University of Delaware's epidemiology programme, said in an interview with CNN that epidemiologists generally look at per capita rates when making comparisons between countries.

The Trump administration's position on testing has been inconsistent. While FEMA is purchasing hundreds of thousands of more tests, Mr Trump has discussed walking back federal funding for local coronavirus testing sites.

The sites - called Community-Based Testing Sites - were meant to provide testing access to critical spots throughout the country. The FDA is currently working to approve individuals to self-administer nasal swab tests at testing sites, which will likely trigger the federal government reducing the amount of personal protective equipment and the number of trained health workers manning the sites.

The move is indicative of the larger, shifting and sometimes contradictory nature of the federal government's role responding to the coronavirus under the leadership of Mr Trump.

Initially, Mr Trump suggested that the states should deal with the pandemic largely on their own, with the federal government standing by to help out where needed. More recently, however, he has asserted federal dominance over the states.