The United States enters one of the most critical weeks so far in the coronavirus crisis with the death toll exploding in New York, Michigan and Louisiana and some governors calling for a national order to stay at home.

New York is the hardest-hit state with more than 40% of all U.S. deaths and nearly 115,000 reported cases on Saturday.

Bodies of victims of COVID-19, the flu-like respiratory disease caused by the coronavirus, were stacked in bright orange bags inside a makeshift morgue outside the Wyckoff Heights Medical Center in Brooklyn, according to photos provided to Reuters.

U.S. Surgeon General Jerome Adams warned on Fox News Sunday that hard times were ahead but "there is a light at the end of the tunnel if everyone does their part for the next 30 days."

"This is going to be the hardest and the saddest week of most Americans' lives, quite frankly. This is going to be our Pearl Harbor moment, our 9/11 moment, only it's not going to be localized," he said. "It's going to be happening all over the country. And I want America to understand that."

Places such as Pennsylvania, Colorado and Washington, D.C. are starting to see rising deaths. The White House coronavirus task force warned this is not the time to go to the grocery store or other public places.

Most states have ordered residents to stay home except for essential trips to slow the spread of the virus in the United States where over 313,000 people have tested positive and nearly 8,500 have died, according to a Reuters tally.

However, a few churches were holding large gatherings on Palm Sunday, the beginning of Holy Week in Christian churches. 

"We're defying the rules because the commandment of God is to spread the Gospel," said Tony Spell, pastor at the Life Tabernacle megachurch in a suburb of Baton Rouge, Louisiana. He has defied state orders against assembling in large groups and has already been hit with six misdemeanors.

Louisiana has become a hot spot for the virus, on Saturday reporting a jump in deaths to 409 and more than 12,000 cases.

Governor John Bel Edwards told CNN on Sunday that the state could run out of ventilators by Thursday.

White House medical experts have forecast that between 100,000 to 240,000 Americans could be killed in the pandemic, even if sweeping orders to stay home are followed.

President Donald Trump warned on Saturday that there were "very horrendous" days ahead. 

Washington state Governor Jay Inslee, a Democrat, whose state recorded the country's first confirmed COVID-19 infection but has since seen cases flatten after early action to shutter activity, said if other states do not also impose strict measures, the virus will simply circulate.

"It would be good to have a national stay-at-home order," he told NBC News' "Meet the Press" program. "Even if Washington gets on top of this fully, if another state doesn't, it could come back and come across our borders two months from now."

Republican Arkansas Governor Asa Hutchinson, however, defended his refusal to order statewide restrictions, saying the situation was being watched closely and that his more "targeted approach" was still slowing the spread of the virus.

"We will do more as we need to," he told NBC.

(Reporting by Susan Heavey and Amanda Becker in Washington and Daniel Trotta; Writing by Lisa Shumaker; Editing by Daniel Wallis) ((Lisa.Shumaker@tr.com; @LisaLShumaker; +1 312-371-3983))