US President Donald Trump has said he is considering imposing a quarantine on New York in a bid to slow the spread of the coronavirus.
"We'd like to see [it] quarantined because it's a hotspot," he told reporters. "I'm thinking about that."
He spoke as confirmed cases in the state increased to more than 52,000, around half of the total in the US.
But the state's governor, Andrew Cuomo, said he had not discussed such measures with the president.
"I didn't speak to him about any quarantine," he told reporters shortly after he had spoken with Mr Trump by phone.
"I haven't had those conversations," he added. "I don't even know what that means."
New York state has the highest number of cases of Covid-19 in the US.
Speaking before he left to visit a Navy hospital ship in Virginia, Mr Trump said that "New Jersey [and] certain parts of Connecticut" could also be quarantined under the measures.
"We might not have to do it but there's a possibility that sometime today we'll do a quarantine — short term [for] two weeks," he said.
But Mr Cuomo, who was holding a daily press briefing at the time of Mr Trump's comments on Saturday, expressed concern at the idea.
"I don't know how that can be legally enforceable," he said. "And from a medical point of view, I don't know what you would be accomplishing."
"But I can tell you I don't even like the sound of it," he added. "Not even understanding what it is, I don't like the sound of it."
Mr Trump did not provide further details about what a quarantine on New York or other badly hit US cities would look like.
But he said it would be aimed at slowing the spread of the virus to other parts of the US.
"They're having problems down in Florida. A lot of New Yorkers are going down. We don't want that," he said as he left the White House.
Similar quarantine measures in other countries have involved widespread closures, bans on public gatherings and major restrictions on travel in and out of the affected area.