New York Governor Andrew Cuomo said his brother Chris Cuomo, a television anchor at CNN, has tested positive for the novel coronavirus, as cases in the state continued to climb rapidly and deaths rose past the 1,500 mark.

"My brother Chris is positive for coronavirus, we found that this morning. He is going to be fine, he's young, strong - not as strong as he thinks... but he will be fine," Cuomo told a daily briefing on the coronavirus.

"I spoke to him this morning and he is going to be quarantined in his basement."

The personal disclosure came after Cuomo said New Yorkers who had tested positive for the coronavirus increased by more than 9,000 from a day earlier to 75,795, with deaths rising to 1,550 from 1,218.

"The virus is more powerful, more dangerous than we expected," Cuomo told a daily news briefing. "We're still going up the mountain, the main battle is on top of the mountain."