By Jeff Mason and Steve Holland

WASHINGTON (Reuters) – U.S. President Donald Trump urged Americans on Monday to halt most social activities for 15 days and not congregate in groups larger than 10 people in a newly aggressive effort to reduce the spread of the coronavirus in the United States.

Announcing new guidelines from his coronavirus task force, the president said people should avoid discretionary travel and not go to bars, restaurants, food courts or gyms.

As stocks tumbled, Trump warned that a recession was possible, a development that could affect his chances of re-election in November. The Republican president said he was focused on addressing the health crisis and that the economy would get better once that was in line.

“We’ve made the decision to further toughen the guidelines and blunt the infection now,” Trump told reporters at the White House. “We’d much rather be ahead of the curve than behind it.”

Trump has faced criticism for playing down the seriousness of the virus in the earlier days of its spread.

He has sought to portray a competent, coordinated government response in recent days while conceding on Monday that the virus was not under control.

That contrasted with his remarks only a day before, when he called the virus contagious but said the administration had “tremendous control” of it.

“I’m saying we are doing a very good job within the confines of what we’re dealing with,” Trump said when asked about his “control” comment from Sunday. He said his remark then referred to his administration’s response. “If you’re talking about the virus, no, that’s not under control for any place in the world.”

Asked to grade his response on a scale of 1 to 10, Trump gave himself a 10. Critics disagree.

Trump said the worst of the virus could be over by July or August, a more specific and lengthier timeframe than he has previously suggested. He called it an invisible enemy.

“With several weeks of focused action, we can turn the corner and turn it quickly,” he said.

MILLENNIALS KEY

The president’s advisers implored young people to follow the new guidelines to avoid spreading the virus even though they were at lesser risk of a severe case if they contract it. Older people, especially those with underlying health problems, are at the greatest risk if they develop the respiratory disease that has now killed more than 70 Americans.

White House coronavirus coordinator Debbie Birx said the behavior of the “millennial” generation was especially key.

“They’re the ones that are out and about, and they’re the most likely to be in social gatherings and they’re the most likely to be the least symptomatic,” she said. “There are more millennials now than any other cohort and they can help us at this moment.”

Birx said if Americans followed the new guidelines, the United States would see a dramatic difference in the outbreak’s trajectory.

Health officials are hoping the measures will help spread new cases over a longer period of time so as not to overwhelm the U.S. healthcare system as has happened in Italy.

Trump said a nationwide curfew was not under consideration at this point and that it was not necessary to postpone elections over the outbreak.

Normally a cheerleader for the U.S. economy, he acknowledged the possibility of a recession while brushing off another dramatic stock market decline as investors worried about the virus. The benchmark S&P 500 closed down 12% and the Dow 13% on Monday.

“The market will take care of itself,” Trump said, adding it would be very strong once the virus was handled. The president has long considered soaring stock markets to be a sign of his administration’s success.

Trump said the administration had talked regularly about domestic travel restrictions but hoped not to have to put such measures in place.

He said he thought it would still be possible for G7 leaders to meet at the Camp David retreat in Maryland in June. Trump upset European countries, which make up a large part of the G7, by instituting travel restrictions from much of Europe without consulting with those nations first.

Signs of seriousness permeated the White House.

Journalists and staff members had their temperatures taken before entering the complex. Reporters staggered their seating during the news conference, sitting in every other seat in the White House briefing room to implement social distancing measures. The White House has temporarily cut down the number of journalists permitted to come onto the complex on a daily basis.

(Reporting by Jeff Mason and Steve Holland; Additional reporting by Timothy Ahmann, Lisa Lambert and Makini Brice; Editing by Peter Cooney and Bill Berkrot)