President Donald Trump said Monday the United States was “strongly on watch” regarding the spread of the coronavirus in China and reaching the United States.

We are in very close communication with China concerning the virus. Very few cases reported in USA, but strongly on watch. We have offered China and President Xi any help that is necessary. Our experts are extraordinary! — Donald J. Trump (@realDonaldTrump) January 27, 2020

“We are in very close communication with China concerning the virus,” Trump wrote on Twitter. “Very few cases reported in USA, but strongly on watch.”

Five Americans have now been diagnosed with the disease after traveling in Wuhan, China — two from California, one from Arizona, one from Washington state, and one from Chicago.

Trump said he had offered China assistance in controlling the disease where over 2,000 cases have been confirmed.

“We have offered China and President Xi any help that is necessary,” Trump wrote. “Our experts are extraordinary!”

Last week, Trump praised China’s efforts and signaled optimism they had the disease under control.

“China has been working very hard to contain the Coronavirus. The United States greatly appreciates their efforts and transparency,” he wrote on Twitter. “It will all work out well. In particular, on behalf of the American People, I want to thank President Xi!”

China has been working very hard to contain the Coronavirus. The United States greatly appreciates their efforts and transparency. It will all work out well. In particular, on behalf of the American People, I want to thank President Xi! — Donald J. Trump (@realDonaldTrump) January 24, 2020

Trump also said the United States had any spread of the disease under control.

“We have it totally under control. It’s one person coming in from China,” Trump in a CNBC interview on Monday. “It’s going to be just fine.”