Israeli pupils returned to school 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, Reuters reports.

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.