The United States government has expanded its sweeping pause on legal immigration applications to include filings from citizens of an additional 20 countries, including Nigeria, following President Donald Trump’s latest update to his “travel ban” proclamation this week.

A United States official, who requested anonymity, disclosed the internal changes to CBS News, noting that the measures have not yet been formally announced by the authorities.

President Trump expanded the travel ban proclamation to cover 20 additional countries, fully barring immigrants and travellers from five new nations and partially restricting entry from another 15 countries.

The U.S. official told CBS News that the United States Citizenship and Immigration Services has expanded its suspension of immigration cases to include nationals from the countries newly added to President Trump’s earlier proclamation.

As a result, the pause will now affect nationals of Burkina Faso, Mali, Niger, South Sudan and Syria, which are the new countries facing full travel bans under the updated policy.

The suspension will also apply to nationals from Angola, Antigua and Barbuda, Benin, Cote d’Ivoire, Dominica, Gabon, Gambia, Malawi, Mauritania, Nigeria, Senegal, Tanzania, Tonga, Zambia and Zimbabwe.

These countries represent the latest group facing partial entry restrictions under the new proclamation.

Previously, the suspension of immigration cases applied to nationals of Afghanistan, Burundi, Chad, Cuba, the Republic of the Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Laos, Myanmar, Sierra Leone, Somalia, Sudan, Togo, Turkmenistan, Yemen and Venezuela.

In the most recent proclamation, President Trump imposed a full entry ban on citizens of Laos and Sierra Leone, which had earlier been subject to partial restrictions.

Under the latest directive, the fully banned countries are Burkina Faso, Mali, Niger, South Sudan, Syria, Laos and Sierra Leone.

Countries facing partial bans include Angola, Antigua and Barbuda, Benin, Cote d’Ivoire, Dominica, Gabon, Gambia, Malawi, Mauritania, Nigeria, Senegal, Tanzania, Tonga, Zambia and Zimbabwe.

In a statement posted on social media late Thursday, USCIS Director Joseph Edlow appeared to confirm the expansion of the policy.

“USCIS is conducting a comprehensive review of anyone from anywhere who poses a threat to the U.S., including those identified in the President’s latest proclamation to restore law and order in our nation’s immigration system,” Edlow wrote.

Taken together, President Trump’s latest travel ban decree now affects nationals from more than 60 per cent of African countries and approximately 20 per cent of all nations worldwide.

President Trump has argued that the wide-ranging restrictions are necessary to safeguard national security and address concerns about the ability of U.S. authorities to properly vet individuals from the affected countries.

However, critics of the administration have condemned the policy as discriminatory, noting that it disproportionately targets countries in Africa and Asia.