The Department of Homeland Security (DHS) announced yesterday that President Trump had signed a proclamation adding travel restrictions to six more countries, effectively barring potential immigrants from these six countries from entering the United States.

The identified countries are Nigeria, Eritrea, Tanzania, Sudan, Kyrgyzstan and Myanmar. In the statement, DHS Acting Secretary Chad Wolf said that the department is updating the methodology it uses to ensure that other nations are complying with stronger security criteria than in the past. According to DHS, these countries do not meet the performance metrics or information-sharing standards required, and immigrants from these countries will be barred from entry into the US until the countries’ systems are in compliance.

Entry into the U.S. is suspended for all immigrants from Nigeria, Eritrea, Kyrgyzstan and Myanmar except for Special Immigrants, who are eligible for entry based on having provided assistance to the US government. As for Sudan and Tanzania, entry of Diversity Immigrants has been suspended. Diversity immigrant visas are given to immigrants from countries that historically have a low immigration rate into the US.

All six countries have significant Muslim populations, including the Rohingya minority group in Myanmar, who are currently fleeing from government persecution. Trump’s initial travel ban, issued in 2017, also targeted predominantly Muslim countries. That ban has been subject to multiple lawsuits questioning the constitutionality of Trump’s executive order, arguing that it discriminates against Muslims because of their religion. The new ban may be likely to raise similar suits.

The new travel restrictions are scheduled to go into effect on February 22.