Jerusalem residents took cover on Sunday as Iran launched an unprecedented drone and missile attack on Israel.

Blasts rang out across the city and explosions lit the skyline red, while residents stockpiled water and sought shelter in bunkers.

"As you can see it's empty, everybody is running home," said Eliyahu Barakat, a 49-year-old grocery shop owner in Jerusalem's Mamilla neighbourhood.

Barakat said many people visited his shop to stock up on supplies, "water, food, everything."

"Normally we close at one o'clock but we will stay open," he added.

An Israeli army official said Iran had launched over 100 attack drones towards Israel and said more could follow.

Army spokesperson Daniel Hagari warned people to get ready to seek shelter.

"I remind you that no matter where the threat is launched from, when an alarm sounds you must enter the shelter and wait there for no less than 10 minutes," Hagari said.

Michael Uzan, a 52-year-old dentist, said his family had gathered at his father-in-law's house to be together.

They followed the government's instructions, bought non-perishable food and were ready to head to the apartment building's bunker.

He said he expected everyday life to be disrupted over the coming days.

"No work tomorrow. Even meetings, everything is cancelled. For children, schools are closed. I have a daughter who was supposed to take an important exam tomorrow, but everything is cancelled," he told AFP.

Residents of northern Israel also braced for attacks.

"I'm really afraid of war, this is serious," Summer Khalil, 52, told AFP from the Galilee village of Majd al-Krum.

"If I hear the sirens, I don't know what to do, we are near the Lebanese border.

"I bought 30 bottles of water, they were almost the last bottles. There was no milk in the shop," she said.

Israel airspace reopened since 0430 GMT: airport authority

Israel's airspace reopened Sunday at 7:30 am (0430 GMT) after it was closed following Iran's attack on Israel, the Israeli airports authority said in a statement.