“Hundreds of thousands of people had to take refuge in bomb shelters at that time across northern Israel,” military spokesman Lieutenant Colonel Nadav Shoshani told AFP.

The military in an earlier statement said the rocket fire sparked fires, while Israel’s medical emergency service said at least four people suffered “shrapnel injuries”, three of whom in the area of the northern Israeli city of Haifa.

Israel’s civil defence agency has ordered all schools in the country’s north closed following the rocket fire, the latest escalation in nearly a year of cross-border exchanges throughout the Gaza offensive.

Educational activities would not be permitted across northern Israel until at least Monday at 6pm, the military’s Home Front Command said, affecting “hundreds of thousands of children” according to Shoshani.

“In Haifa, a lot of school are closed… and offices are empty”, said resident Patrice Wolff, who works in the medical industry.

He told AFP there was “more and more pressure” coming from Hezbollah as well as from Israeli forces on the Lebanese group.