President Donald Trump warned Tuesday that this week will be "very painful" for the US in terms of coronavirus-related casualties with nearly 400,000 people in the country sickened by the virus.  

Speaking at a White House coronavirus task force briefing, the president thanked Americans for following social distancing guidelines to curb the spread of the virus.

"During this painful week, we see glimmers of very, very strong hope. This will be a very painful week…at least part of next week, probably," said Trump. "If one person dies, it's a painful week, and we know that's unfortunately going to happen. This is a monster we're fighting."

He said indications showed the country's strategy to fight the disease is "totally working."

"Every American has a role to play in winning this war, and we are going to win it very powerfully," Trump added.

As of Tuesday evening, the death toll from the virus had exceeded 12,000 in the US and it leads all countries worldwide in the number of infections, with data from Johns Hopkins University showing 387,547 confirmed cases.

The novel coronavirus, officially known as COVID-19, has spread to over 184 countries and regions since it first emerged in the Chinese city of Wuhan in December.

More than 81,200 have died worldwide with more than 1.4 million infected.