According to a memo published by the US Citizenship and Immigration Services (USCIS), President Donald Trump’s administration on Tuesday halted immigration processing for people from the 19 countries already subject to US travel restrictions imposed in June, NBC News reports.

USCIS has assessed that this decision may delay the processing of certain pending applications and has weighed this impact against the agency’s imperative to ensure the most complete vetting of applicants, the agency said in its four-page policy memo.

Ultimately, USCIS has determined that the burden of processing delays on certain applicants is necessary and appropriate in this case compared with the agency’s obligations to protect national security, it added.

The decision applies to both applicants for US green cards and other citizens.

The suspension affects citizens of 19 countries deemed high risk by the Trump administration.

The list is primarily targeted at countries in Africa and Asia.