The United States warned Americans on Thursday to return home or stay abroad indefinitely, while Senate Republicans unveiled a $1 trillion (£865.58 billion) economic stimulus plan to provide funds directly to businesses and the American public, as the number of coronavirus cases in the country surged past 13,000.

The fast-spreading respiratory illness has shattered most patterns of American life: shuttering schools and businesses, prompting millions to work from home, forcing many out of jobs and severely curtailing travel.

"If you choose to travel internationally, your travel plans may be severely disrupted, and you may be forced to remain outside of the United States for an indefinite timeframe," the U.S. State Department said.

At the same time, the Trump administration said it was not ruling out a temporary halt to all U.S. passenger air travel.

"Everything's on the table," Deborah Birx, White House coordinator for the coronavirus task force, told Fox News Channel.

The United States could announce restrictions on travel across the U.S.-Mexico border as soon as Friday, limiting crossings to essential travel, two officials briefed on the matter said.

STIMULUS PACKAGE

The U.S. Senate unveiled details of a $1 trillion-plus coronavirus bill on Thursday intended to help the U.S. economy weather the impacts of the growing outbreak. President Donald Trump has been eagerly calling for that package.

It would be Congress' third emergency coronavirus bill following a $105 billion-plus plan covering free coronavirus testing, paid sick leave and expanded safety-net spending, and an $8.3 billion measure to combat the spread of the highly contagious pathogen and develop vaccines.

Trump, speaking with several state governors by phone from the headquarters of the Federal Emergency Management Agency, said the government would help out the U.S. auto industry "a little bit." It might also consider a relief package for the hospitality industry.

The plunging stock market and surging U.S. death toll has caused Trump to sharply change his tone on the disease this week, demanding urgent action after spending weeks downplaying the risks.

More than 13,000 people across the United States have been diagnosed with the illness called COVID-19 and more than 196 have died, with the largest numbers so far in Washington state and New York.

Washington state on Thursday reported eight more deaths from the coronavirus pandemic, bringing the death toll there to 74, the most of any U.S. state.

New York State tested 8,000 patients overnight and ordered three-quarters of state employees to work from home, while officials in New York and neighboring New Jersey said they expected the number of cases in those states to spiral into the thousands.

"We don't have the results of the 8,000 tests, but when you do 8,000 tests, the numbers are going to go up exponentially," New York Governor Andrew Cuomo told CNN.

There are no approved treatments or vaccines for COVID-19, but several options are being tested.

NEW YORK A 'GHOST CITY' AFTER DARK

New York City, where many young people last weekend packed local bars and restaurants, has been eerily deserted after nightfall.

"It's a skater's dream," said Dyanna Hernandez, 20, who had joined a dozen friends in Manhattan's Union Square to enjoy the freedom of what she called a "ghost city" after three days stuck at home. "I can't really be quarantined."

With the United States slow to roll out mass testing for the virus that has infected more than 244,000 people worldwide, officials fear the number of known cases of the respiratory illness that can lead to pneumonia lags far behind reality.

A new drive-through testing site is due to open on Friday at a community college in New Jersey's Bergen County with the capacity to collect 2,500 specimens per week, significantly ramping up the state's ability to test its residents.

New Jersey health commissioner Judy Persichilli said she expected the number of cases to "rise exponentially" in step with wider testing, and said officials may not be able ultimately to reduce the number of people who become infected.

The fast-spreading epidemic, which has killed over 10,000 globally so far, has drawn comparisons with traumatic periods such as World War Two, the 2008 financial crisis and the 1918 Spanish flu pandemic.

The number of Americans filing for unemployment benefits surged by the most since 2012 to a 2-1/2-year high last week, as companies in the services sectors laid off workers with businesses shutting down due to the pandemic.

One sector where employees were busy -- and unable to work from the safety of home -- was the nation's 3 million janitors, housekeepers and maids, who are on the front line of the war against the virus, often working overnight and weekends to deep clean offices, airports and hotels.

"Everyone is scared," said Ali, who works for ABM, a maintenance and cleaning firm that employs more than 140,000 people. "We just keep going, let's do what we can."