The World Health Organization's top official criticized some nations for not doing enough to detect and contain the deadly coronavirus that's infected more than 174,000 people across the world.

There's been a rapid escalation of COVID-19 cases over the past week, WHO Director-General Tedros Adhanom Ghebreyesus told reporters at a virtual press conference Monday. "But we have not seen an urgent enough escalation in testing, isolation and contact tracing, which is the backbone of the response," he said.

"We have a simple message for all countries: Test, test, test. Test every suspected case. If they test positive, isolate them and find out who they have been in contact with two days before they developed symptoms and test those people, too," Tedros said.

Tedros didn't single out any one country, but state and local leaders in the U.S. have heavily criticized the Trump administration and U.S. Centers for Disease Control and Prevention for delaying and limiting who could get tested in the U.S.

At the beginning of the outbreak, the CDC limited testing to people who had recently traveled to China and showed symptoms, or people who were symptomatic and exposed to someone with a confirmed case. The agency has since expanded its guidelines to include people showing symptoms who are already in the hospital or with underlying health conditions.

"For any country, one of the most important things is the political commitment at the highest level," Tedros said. "All countries should be able to test all suspected cases. They cannot fight this pandemic blindfolded; they should know where the cases are."

On Friday, New York Gov. Andrew Cuomo said the state was ramping up its testing, having just received federal approval to allow 28 labs across the state to begin running coronavirus tests. He said the state should be able to process 6,000 a day starting next week. The state had been able to run a total of just 3,000 tests so far, he said.

Federal regulators gave private labs, including LabCorp and Quest Diagnostics, approval on Feb. 28 to start running coronavirus tests, and Vice President Mike Pence announced expanded testing capabilities across the U.S. over the weekend.

"There's no doubt that we are missing cases. I think we need to be realistic about this," said Dr. Maria Van Kerkhove, head of WHO's emerging diseases and zoonosis unit.

In treating patients, Tedros said, countries should first treat people who have underlying conditions. Some countries have converted stadiums and gyms to care for mild cases to free up hospitals for severe and critical cases, he said.

In Korea, where the virus spread rapidly last month, health officials rolled out an aggressive testing regime that processed tests for more than 259,000 people and confirmed more than 8,000 infections, according to the Korean CDC. In the U.S. more than 22,000 people have been tested at CDC and public health labs, according to the U.S. CDC. That does not include tests run by commercial labs, some of which were authorized last week to begin automated testing.

"Once again, our key message is: Test, test, test. This is a serious disease. Also the evidence we have suggests that those over 60 are at highest risk. Young people, including children, have died," Tedros said.

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