The New York Mayor’s Office has told United Nations diplomats that coronavirus has already spread widely through the city and could linger as a health threat until as late as September, diplomatic sources have told Foreign Policy.

“Everyone in New York should assume that they have been in contact with Covid-19,” city officials said.

The news comes as New York Governor Andrew Cuomo, called for President Donald Trump to mobilise the military to help fight the coronavirus pandemic.

Writing in the New York Times, he said that he wants federal troops to help expand hospital capacity.

The diplomatic briefing to UN diplomats was led by Penny Abeywardena, commissioner in the Mayor’s Office for international affairs and included representatives from the department of health and mental hygiene.

While offering advice to diplomatic delegations as to how to get through the crisis, no special services, such as testing, were promised.

In his op-ed — an open letter to President Donald Trump — Governor Cuomo admits that it is now unlikely that the spread of the virus can be slowed to a rate at which state healthcare systems can cope. However, he says that is not a reason not to try.

His call for military involvement to tackle the growing crisis is apt given this is effectively a natural disaster.

“States cannot build more hospitals, acquire ventilators or modify facilities quickly enough. At this point, our best hope is to utilise the Army Corps of Engineers to leverage its expertise, equipment and people power to retrofit and equip existing facilities — like military bases or college dormitories — to serve as temporary medical centres. Then we can designate existing hospital beds for the acutely ill,” he writes.

Mr Cuomo is particularly focused on ramping up hospital capacity. New York State has approximately 53,000 hospital beds and 3,000 ICU beds with ventilators. Of those ICU beds, 80 per cent are currently occupied.

The governor also asks for the Food and Drug Administration and Centres for Disease Control and Prevention to stop over-regulating the testing process, saying that allowing local labs the ability to test was a good first step, but more needs to be done.

New York state has conducted 442 tests since Saturday. He says that the state could be conducting 6,000 tests a day by next week.

In addition he calls for federal standards for when businesses, schools and events should be closed down to stop people crossing state lines to use services elsewhere, which is counterproductive. Mr Cuomo also calls for federal assistance to aid in meal programmes, childcare and the overall cost to local economies.

In a press conference on Sunday, Mr Cuomo called for the closing of all New York City schools, but not without a plan to offer childcare and meal programmes. So far, Mayor Bill DeBlasio has resisted shutting down the nation's largest school district and sending 1.1 million students home.

As of Sunday, New York state has 729 confirmed cases, an increase of 69. There have been three deaths. Of the total cases, 131 are hospitalised and 65 patients are in intensive care.