The mayors of New York City and Los Angeles have issued grim predictions about the coming weeks as their cities face rising numbers of residents infected with the coronavirus.

New York Mayor Mike De Blasio appeared on Good Morning America on Friday morning, suggesting the city would be shut down until the end of May and nearly half of its denizens will become infected with coronavirus.

“I think we need to be ready for that,” Mr De Blasio said. “Unfortunately we think it’s going to go through April and in to May. It’s just a blunt reality.”

He went on to say that more than “half the people in this city will ultimately be infected.”

Mr De Blasio did note that for the majority of infected, there “will be very little impact, in truth - it’s like having a cold or flu and you get through it in seven to 10 days.”

He went on to say that 20 percent would have more severe symptoms and a small percentage would die from the virus.

Los Angeles Mayor Eric Garcetti had similar concerns, telling Business Insider the projections were "horrifying."

"Will we have hundreds of thousands of deaths, or tens of thousands of deaths? That's what keeps us up. These are people who all know, who each one of us will know. It'll be our friends, it'll be our family, it'll be people whom we love dearly," Mr Garcetti said.

During the interview, Mr De Blasio insisted that aid must continue to come from the federal government and criticised President Donald Trump for suggesting the city doesn’t need extra ventilators.

Though Mr Trump could - and, for a time, seemed ready to - use the Defense Production Act and instruct corporations to begin manufacturing ventilators, the New York Times reported that corporate heads have “lobbied the administration against using the act.”

Mr Trump said the Defense Production Act scared the “business community” because “you’re going to nationalize an industry.”

The Defense Production Act does not nationalize any industries, but simply gives the government the power to temporarily redirect what companies produce and how they allocate their resources.

“It has to keep coming. The president has to make that contract with a company that can make ventilators. Without a ventilator, doctors can’t save lives,” Mr De Blasio said. “They’re going through hell. Look at what they are having to deal with.”

Mr De Blasio said he didn’t want to give people “false hope” and said the city had “a really tough battle ahead.”

“This idea of Easter is a false hope. It would be better if [Mr Trump] was honest with people,” he said.

Mr Garcetti echoed Mr De Blasio's sentiments.

"Giving people false hope will crush their spirits and kill more people," he said. "Crush their spirits, revert their actions, and kill more people."

The virus has killed 365 people in New York City and infected 23,000. New York City announced between Wednesday and Thursday, 177 people died of the virus.