Trump announced the temporary suspension will be invoked through an executive order to prevent further spread of the coronavirus and protect jobs as millions apply for unemployment benefits while businesses shutter under government lockdowns.
"In light of the attack from the Invisible Enemy, as well as the need to protect the jobs of our GREAT American Citizens, I will be signing an Executive Order to temporarily suspend immigration to the United States!" he said in the tweet.
He did not say when the order would be issued or how long it will last. The legal basis and reasoning behind the order were also not made clear.
The announcement came hours after the president held a coronavirus task force briefing where his administration explained the instructions given to state governors for the gradual reopening of their economies without mention of a possible immigration ban.
Trump has previously exercised his executive powers amid the pandemic to restrict entry to the United States for asylum seekers and undocumented immigrants.
In March, citing "grave public health consequences of mass uncontrolled cross-border movement," Trump announced he was closing the U.S. borders to Mexico and Canada for all but essential travel. Migrants captured unlawfully crossing into the United States at either crossing would be sent back without detention or processing to whichever North American nation they entered from.
Trump has already banned travel to the United States from Europe, Britain, Ireland, Iran and China due to the threat of COVID-19.
The first travel restriction, instituted against China in late January, was met at the time with criticism from the Asian nation and the World Health Organization, but the president has championed the restriction as having prevented further spread of the virus within the United States.
Since the first person in the United States was diagnosed with the coronavirus in late January, the virus has spread exponentially within the country, infecting nearly 800,000 Americans and killing more than 42,300, according to a case tracker of the virus by Johns Hopkins University.
Some 22 million Americans applied for unemployment last month as increasing numbers of people have been laid off or found themselves without work due to lockdowns restricting which businesses may operate.
The immigration suspension is expected to attract widespread criticism from Democrats, and Rep. Joaquin Castro, D-Texas, swiftly condemned it via Twitter as an attempt to exploit the global health crisis.
"This action is not only an attempt to divert attention away from Trump's failure to stop the spread of the coronavirus and save lives, but an authoritarian-like move to take advantage of a crisis and advance his anti-immigrant agenda," said Castro, who is chairman of the House Hispanic Caucus and vice chairman of the House foreign affairs committee.
Rep. Judy Chu, D-Calif., derided the move on Twitter as "an insult to the millions of immigrants" risking their lives as essential workers, a sentiment shared by Rep. Jerry Nadler of New York and chairman of the House judiciary committee.
"We need to come together to beat this disease, not attack each other and divide the country," he said. "This is a disgrace -- demonizing so many of those who are serving on the front lines against COVID while the President shows himself as small and ineffective."