Story highlights 8 countries are now affected

The new restrictions take effect Oct. 18

Washington (CNN) The Trump administration has unveiled new travel restrictions on certain foreigners from Chad, Iran, Libya, North Korea, Somalia, Syria, Venezuela and Yemen as a replacement to a central portion of its controversial travel ban signed earlier this year.

The new restrictions on travel vary by country and include a phased-in approach beginning next month.

"Making America Safe is my number one priority. We will not admit those into our country we cannot safely vet," President Donald Trump tweeted just after his administration released the details of the restrictions Sunday night.

Making America Safe is my number one priority. We will not admit those into our country we cannot safely vet.https://t.co/KJ886okyfC — Donald J. Trump (@realDonaldTrump) September 24, 2017

In a statement Sunday night, the White House called the new restrictions a "critical step toward establishing an immigration system that protects Americans' safety and security in an era of dangerous terrorism and transnational crime."

"We cannot afford to continue the failed policies of the past, which present an unacceptable danger to our country," Trump said in the White House statement. "My highest obligation is to ensure the safety and security of the American people, and in issuing this new travel order, I am fulfilling that sacred obligation."

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