Amid heightening regional tensions, Israelis have been provided with guidance on what to do in the event of attacks on the country, while supermarkets are reporting a spike in sales for basic goods.

Israel’s Victory supermarket chain said sales of some goods are up 30%, compared to regular sales. It told CNN that people mostly buy canned food, cereals, pasta, toilet paper, frozen meat, bottled water and hygiene wipes.

The Jerusalem municipality has issued instructions to people on what to do in the event of the city coming under attack, distributing a file with a list of parking lots that will be used as shelters and a list of bomb shelters. It said residents must be able to reach bomb shelters in 90 seconds.

“Residents are advised to clean and prepare their bomb shelters in advance,” the file says.

Residents are also advised to stock enough water and food for three days and to buy batteries and flashlights in addition to medications.

“Residents should be ready for power cuts that might last several days. They should also be ready to stay in bomb shelters for several days,” the file says.

There have also been disruptions to flights in and out of Israel, with Air India becoming the latest international carrier to suspend services to Tel Aviv.

Leader of the Islamic Revolution Ayatollah Ali Khamenei said Wednesday it was Iran’s “duty” to avenge the death in Tehran of Hamas’ political leader Ismail Haniyeh.