President Donald Trump's mic was on before he delivered a speech Wednesday night on the US response to the coronavirus outbreak, which has infected more than 1,300 people in the US and killed 38.

In an address from the Oval Office, Trump said he would ask Congress to provide payroll tax relief and waivers for small businesses. He also announced a 30-day ban on travel by foreign nationals to the US from most of Europe.

C-SPAN caught Trump in the moments before he delivered the speech.

"Oh f---," Trump said with a sigh while his microphone was on before delivering the speech. "Uh-oh, I've got a pen mark."

He then asked his staff for "any white stuff."

The moment was posted online by several Twitter users:

C-SPAN also caught the moments after Trump delivered his speech as the cameras were still rolling.

"OK," Trump said with a sigh as he began to remove his mic from his lapel.

The cameras continued rolling for another 10 seconds before the stream cut out.

Trump's comments came hours after the World Health Organization declared the coronavirus outbreak a pandemic. COVID-19, the illness caused by the virus, has spread to more than 100 countries and has infected more than 121,000 people.