US President Donald Trump says he is considering sealing off New York and parts of neighbouring states in response to the worsening coronavirus crisis.

“There’s a possibility that sometime today we’ll do a quarantine, short-term, two weeks on New York, probably New Jersey, certain parts of Connecticut,” Trump said on Saturday before departing the White House.

He said New York residents are leaving the state and “we don’t want that,” adding that the quarantine would be “enforceable” and would restrict travel outside the state.

He later added that, if the decision was made, “it won’t affect trade in any way”.

Federal restrictions on travel would be an extraordinary measure by Trump and a significant escalation on the current orders from the governor for New York residents to remain at home, which are largely being enforced through social pressure.

Trump’s statement was met with surprise by New York Governor Andrew Cuomo, who said Trump did not mention a state-wide quarantine in a phone call between the leaders on Saturday.

“I don’t even know what that means. I don’t know how that could be legally enforceable,” Cumo said at a press briefing. “I don’t even like the sound of it.”

Cuomo said his state has more than 52,000 reported cases of coronavirus, amounting to nearly half of all reported cases in the US.

Meanwhile, New York is preparing for an apex in cases within 14 to 21 days and is stockpiling medical equipment, Cuomo said.

“When that curve hits the highest point it is too late to try to acquire what you need,” Cuomo said at a press conference. “Acquire what you need now.”

The US leads the world in reported coronavirus cases at more than 105,000, including more than 1800 deaths, according to data compiled by Johns Hopkins University.

Globally, cases of the coronavirus topped 600,000 on Saturday, just two days after the world hit the landmark total of half a million.

To help alleviate the state’s embattled health care providers, a US navy hospital ship will depart to New York on Saturday and is expected to dock there on Monday.

Trump will see the ship off during a ceremony on Saturday.

Cuomo added that his state has postponed its presidential primary from April to June – adding to a growing list of over 10 states – amid the pandemic.

Meanwhile, the United Nations announced that it will be donating a quarter of a million protective face masks stored at UN headquarters in New York to the United States.