U.S. President Donald Trump's decision to suspend immigration to the United States for 60 days to stop those applying for permanent residency from taking American jobs has drawn criticism from immigration advocates who brand it a "distraction" amid the COVID-19 pandemic.

"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 into the United States!" the president tweeted Monday night.

Trump said he signed the executive order on Wednesday to "ensure that unemployed Americans of all backgrounds will be first in line for jobs as our economy opens."

Former US secretary of state John Kerry told CNN that the immigration order was "a sideshow, an effort to divert attention".

The executive order won't bar immigrants already living in America seeking green cards, or the 85,000 workers a year given H-1B visas nor seasonal farm workers. It also will not stop people using temporary visas for work or travel.

Over the past three years, the number of visas issued to people who want to immigrate to the US fell to 462,422 in the 2019 fiscal year, down from 617,752 in 2016.

In 2019, the State Department issued about 462,422 immigration visas, according to The Washington Post. Citizenship and Immigration Services, part of the Department of Homeland Security, processed and approved nearly 580,000 green cards.

At least 6 million US healthcare workers were born abroad, including 29 percent of all doctors, 38 percent of home health aides and 23 percent of retail store pharmacists, according to the Migration Policy Institute.