Gov. Andrew M. Cuomo said that health and economic officials from the states were starting work immediately on developing strategies for easing restrictions that have brought much of daily life to a halt.

Of the seven states, only Massachusetts has a Republican governor.

The officials participating in the effort, Mr. Cuomo said, would “study the data, study the research, study the experience of other countries and give us guidelines and parameters to go forward.”

[Get the latest news and updates on the coronavirus in the New York region.]

“The worst is over” if New Yorkers remain resolute, Mr. Cuomo said.

Mr. Cuomo said on Monday, for the first time, that he believed the most horrific phase of the coronavirus outbreak may have passed.

“I believe the worst is over if we continue to be smart,” Mr. Cuomo said at his daily briefing. “I believe we can start on the path to normalcy.”