JERUSALEM, Sept 1 (Reuters) - Israeli pupils returned to school on Wednesday with mask requirements and mandatory COVID-19 testing aimed at stemming a surge in coronavirus cases that has overshadowed the highly-vaccinated country"s reopening. Health officials worry the launch of a new school year - with most students attending in-person - will exacerbate the current wave ahead of this month"s Jewish holiday season, potentially forcing another national lockdown. New infections have soared since the emergence of the Delta variant, reaching a pandemic-high 10,947 on Tuesday among Israel"s 9.3 million population. Under what he calls a "living with COVID" policy, Prime Minister Naftali Bennett has pressed ahead with the new school year, in part by ramping up vaccine booster shots and requiring testing for students and unvaccinated instructors. Visiting a school in Israel"s Negev desert, Bennett said the testing effort - some 2 million tests were conducted - was the largest in Israel"s history. "After a year of Zooming, a difficult year of fading and staring in front of the screens, I want to wish you, the students of Israel, this one thing: May the year of screens be done away, and a year of experiences begin," Bennett said. But Bennett"s government announced the new measures just days before classes resumed, drawing criticism from parents who say they were given little time to prepare. Gal Altberg said she was excited to send her children, in 1st and 3rd grade, back to school but worried there might still be a lockdown amid the rise in infections. "The policy is still up in the air, the government changes things around but we are hoping for (the best), and we are hoping that the vaccinations will help," Altberg, 41, said. Students under 12 - the minimum age of eligibility for the vaccine - must present their teachers with a parent"s note confirming they performed a rapid test at home and received a negative result. Such testing is not required beyond the first day. But officials say further testing could be done before or after the Jewish holidays, where large family gatherings are common. The first of those festivals is on Sept. 6 and the last on Sept. 30. In areas with particularly high infection, schools where less than 70% of students are vaccinated are required to conduct remote learning. Around 10% of Israeli students will attend school online on Wednesday, according to the YNet news website.