Amid criticism of the US authorities' response, New York deployed the National Guard for the first time during the crisis to help contain the spread of the disease from an infection-hit suburb.

"It is a dramatic action, but it is the largest cluster in the country. This is literally a matter of life and death," said state governor Andrew Cuomo.

"People are scared, it's an unusual situation to be in," Miles Goldberg, who runs a New Rochelle bar, told AFP.