President Donald Trump plans to declare a national emergency on Friday over the coronavirus outbreak, invoking the Stafford Act to open the door to more federal aid for states and municipalities, according to two people familiar with the matter.

Trump is under increasing pressure to act as governors and mayors nationwide step up actions to mitigate the spread, closing schools and canceling public events. The president said he will hold a news conference at 3 p.m. in Washington.

Senate Democrats have urged Trump to invoke the Stafford Act and other disaster declaration requests they say would free up more than $42 billion in funding for states available in the Disaster Relief Fund.

An emergency declaration would allow a state to request a 75% federal cost-share for expenses that include emergency workers, medical tests, medical supplies, vaccinations, security for medical facilities, and more, according to a letter Democrats sent the president earlier this week.

Only a few emergency declarations for public health threats have been made since the 1960s, and only two have targeted disease outbreaks, when President Bill Clinton in 2000 declared emergencies in New York and New Jersey in response to the West Nile Virus.