On Thursday, US President Donald Trump issued a proclamation extending the suspension of issuance of work visas and green cards.
Trump imposed the measures in April and June to protect American workers' job opportunities amid a rise in unemployment due to the COVID-19 pandemic.
The proclamation came hours before the president's executive order on the immigration restrictions was set to expire.
The order will now expire at the end of March, extending into the first term in President-elect Joe Biden's office, who has vowed to reverse Trump's immigration policies.
The proclamation said allowing immigrant workers into the country would "pose a risk of displacing and disadvantaging US workers during the economic recovery following the COVID-19 outbreak".
"The effects of COVID-19 on the United States labour market and the health of American communities is a matter of ongoing national concern.
"And the considerations present in Proclamations 10014 and 10052 have not been eliminated," Trump wrote in the proclamation.
The president first imposed restrictions on the issuance of green cards for immigrants in April and expanded it in June to limit several other work visas.
They include new H-1B tech worker visas, H-2B seasonal worker visas, specific J work and education exchange visitor visas and L executive transfer visas.
The proclamation said the recent surge in COVID-19 cases had surpassed previous highs in June.
This, in addition to the implementation of pandemic-related restrictions, has placed further strain on US businesses, it said.
"The effect of recently approved vaccines and other treatments has not yet been fully realised for the US labour market.
"While the November overall unemployment rate in the United States of 6.7 per cent reflects a marked decline from its April high, there were still 9,834,000 fewer seasonally adjusted nonfarm jobs in November than in February of 2020," the proclamation added.
The order applies only to foreigners outside the US and does not yet have permission to enter.
Those who already have permanent residency are not affected, and there are exceptions for certain people, including spouses and children of US citizens, the News Agency of Nigeria reports.