State government and public health leaders have warned Americans to resist the impulse to ease social-separation measures at the first glimpse of progress, as the U.S. death toll surpassed 16,500.<br /><br />Calls for heightened vigilance, countering talk from the Trump administration of reopening the economy next month, came as new evidence emerged that stay-at-home restrictions were working to flatten the curve of infections in New York state, the US epicenter of the pandemic.
