U.S. President Donald Trump has not been tested for COVID-19, said the White House on Monday night.

"The President has not received COVID-19 testing because he has neither had prolonged close contact with any known confirmed COVID-19 patients, nor does he have any symptoms," White House press secretary Stephanie Grisham told reporters.

"President Trump remains in excellent health," she added. "His physician will continue to closely monitor him."

The announcement came as several U.S. lawmakers, including incoming White House chief of staff Mark Meadows, are self-quarantining because of exposure to an attendee of last month's Conservative Political Action Conference (CPAC), who has tested positive for COVID-19.

Meadows has tested negative for COVID-19, according to a spokesperson.

The attendee contracted the disease before the CPAC, held in National Harbor, Maryland, just south of Washington D.C., on Feb. 26-29, according to the American Conservative Union, organizer of the event.

Trump and Vice President Mike Pence spoke at the CPAC.

Speaking to reporters at a briefing at the White House Monday evening, Pence also said that he has not been screened for COVID-19, later adding that there has been "no recommendation" that he be tested.

As of Monday night, more than 600 cases have been reported in the United States with 22 deaths, according to real-time data maintained by the Center for Systems Science and Engineering at Johns Hopkins University.

A number of U.S. states have declared a state of emergency to try and combat COVID-19.