The nation of Israel will reinstate its indoor mask mandate next week, once again requiring people to wear coverings over their mouths and noses to prevent infections in an effort to slow the viral spread as COVID-19 cases increase.

Israel's coronavirus czar Nachman Ash told reporters Thursday that 169 new cases were recorded, the highest daily total in months for a country with one of the highest inoculation rates in the world. He recommended that Israeli citizens avoid flights abroad, especially if they have not yet been vaccinated.

"I call on the public to consider whether traveling abroad is essential. It is highly advisable to avoid non-essential travel abroad," he said. "This is not the right time to fly with children who are not vaccinated."

Ash also urged anyone who has come into contact with a COVID-19 positive person to get tested immediately, even if they have been vaccinated, and advised that Israelis obey quarantine restrictions after travel.

"If a child has been abroad and arrives at school the next day, this is wrong. And everyone should say that to him and to his parents," he said.

When pressed by reporters, Ash could not explain why COVID-19 cases were rising suddenly. He admitted that it is impossible to stop new coronavirus variants from entering the country without closing the borders completely, which the government is reluctant to do.

The Israeli Health Ministry is not yet recommending a return to restrictions on public gatherings, Ash said.

According to the Times of Israel, the Delta variant of the SARS-CoV-2 virus is believed to be responsible for 70% of the new cases recorded in Israel in the past few weeks. The number of new cases reported has exceeded 100 for four days in a row this week.

Previously, Israel was celebrated as a successful model for defeating the coronavirus with widespread vaccinations and returning to the pre-pandemic normal. The country boasts a 57% full vaccination rate for its entire population.

The first indoor mask mandate ended June 15 as various coronavirus restrictions were lifted because people were presumably inoculated from the COVID-19 disease.

The "Delta variant" is a mutation of the SARS-CoV-2 virus that was discovered in India and has come to dominate international headlines because of concerns it is a more transmissible version of the virus. There is data that suggests, however, that the Delta variant has a lower case-fatality rate than other versions of the virus.

President Joe Biden made a public service announcement on his social media pages Thursday morning warning about the dangers of the Delta variant and encouraging those who have not yet been vaccinated to receive their vaccines. He shared a video of National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci answering several questions about the variant.

"Here's the deal: The Delta variant is more contagious, it's deadlier, and it's spreading quickly around the world – leaving young, unvaccinated people more vulnerable than ever. Please, get vaccinated if you haven't already. Let's head off this strain before it's too late," Biden said.

Here’s the deal: The Delta variant is more contagious, it’s deadlier, and it’s spreading quickly around the world –… https://t.co/yUesHruD2i

— President Biden (@POTUS) 1624536674.0

The U.S. Centers for Disease Control and Prevention's COVID-19 guidelines currently state that Americans who have been fully vaccinated against the virus, receiving both doses of a vaccine, do not need to wear masks or face coverings indoors or outdoors because they have been immunized.