The Trump administration is finalizing the addition of a few other countries to the travel ban, and on Sunday, when the existing ban expires, President Trump is expected to sign a new executive order, according to the Wall Street Journal

The new travel ban is expected to lay out more specifically targeted restrictions, the Journal reports.

A White House official would not confirm the report, saying only, "The Trump Administration will ensure we only admit those who can be properly vetted and will not pose a threat to national security or public safety." The White House would not say how many countries would be affected by the new order or what the restrictions will look like.

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The Journal says that the rules will affect eight or nine countries, and those rules will vary based on factors such as their cooperation with U.S. mandates and the threat posed by each country. Further, unlike the current ban, the new rules will not expire, and the Trump administration will add or remove restrictions to countries as conditions change.

Mr. Trump signed his original ban in January, banning travel from seven countries: Yemen, Syria, Afghanistan, Libya, Somalia, Iraq and Iran. As legal challenges continued to block the implementation of the ban, the president signed a revised ban targeting the same countries, minus Iraq.

The Trump administration has said that the intent of the ban is to improve screening and prevent terrorists from entering the country, and to evaluate how well countries are complying with U.S. vetting procedures.

This is a change that seems to be in keeping with a tweet from the president last week, in which he said that the travel ban "should be far larger, tougher and more specific."

The travel ban into the United States should be far larger, tougher and more specific-but stupidly, that would not be politically correct! — Donald J. Trump (@realDonaldTrump) September 15, 2017

The administration continues to defend its ban from lawsuits. Next month, on Oct. 10, the Supreme Court will hear arguments on the constitutionality of the revised travel ban.