New York Governor Andrew Cuomo extended the state's shutdown order Thursday until May 15, citing data showing conditions were improving but insisting on the need to maintain vigilance.

The governor pointed to falling rates of hospitalization and patients admitted to intensive care, but said infection rates would have to decrease significantly before the economy could begin re-opening.

"I would like to see that infection rate get down even more," Cuomo said at his daily briefing, reporting that 606 more people had died in the US COVID-19 epicenter, the lowest daily toll in 10 days.

"I don't want to project beyond that period," he said. "One month is a long time."

The announcement came on the eve of the implementation of a directive forcing New Yorkers to wear face coverings in public places where they cannot stay six feet (1.83 meters) apart.

In a hopeful sign, Cuomo said New York state -- where at least 11,586 people have died from COVID-19 and well over half a million have tested positive -- would donate 100 ventilators each to hard-hit New Jersey and Michigan and 50 to Maryland.

"We understand about sharing resources like we've never understood before, and we understand about sharing among states and how good people were to New York when we needed it," Cuomo said.