US President Donald Trump on Wednesday announced a new travel ban that will block entry to the U.S. for citizens from 12 countries and impose restrictions on visitors from seven others.

The measure, set to take effect at 12:01 a.m. Monday, marks a revival of one of Trump’s most controversial first-term policies — this time with advance notice to avoid the airport disruptions seen during the 2017 rollout.

Among the 12 nations facing a full travel ban are: Afghanistan, Myanmar, Chad, the Republic of Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan, and Yemen. Meanwhile, travelers from Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan, and Venezuela will be subject to additional restrictions.

In a social media video, Trump linked the decision to a recent terrorist attack in Boulder, Colorado, highlighting visa overstays as a national security concern.

The suspect in that incident is from Egypt, which is not among the countries listed in the new policy. According to the Department of Homeland Security, the individual had overstayed a tourist visa.

Trump had hinted at reintroducing the ban after returning to office in January, and with backing from a prior Supreme Court ruling, he is seen to have a stronger legal footing this time.