It read: “You must enter a protected area immediately and remain there until further notice.”

The message was sent by the Israel Defense Forces's Home Front Command and ended with the phrase "life-saving instructions”.

People began to head for shelter in safe rooms as missiles were launched towards Israel from Iran.

The sirens sounding across the country were heard by millions.

As the wail of the alarm rang outside, we moved to the shelter in the BBC’s Jerusalem Bureau - a secure part of the building with no windows.

We could hear frequent booms as missiles flew overhead and were intercepted by Israel’s defence system.

Videos captured here and elsewhere shared on social media showed streams of light as the missiles flew over Israel - and clouds of smoke as they were intercepted or detonated on impact.

“There’s loads of them,” a contact exclaimed in a video filmed in southern Israel that shows circles of light in the night sky.

At about 20:00, the IDF said its aerial defence array was identifying and intercepting the launches, and called on people to “remain in a protected space until further notice”.

It continued: “The explosions you are hearing are from interceptions and fallen projectiles.”

Concern had been mounting across Israel as reports emerged early in the evening that Iran was preparing a strike.

It came hours after Israeli troops invaded Lebanon, in what its military calls a "limited, localised and targeted" ground operation against Hezbollah.

Iran’s Revolutionary Guards said it launched the missiles in retaliation for recent attacks that killed the leaders of Hezbollah and Hamas, as well as a senior Iranian commander.

As missiles flew overhead, messages streamed in from people in different parts of the country, waiting in their safe rooms.

“There’s a lot of alarms all the time so we’re in the safe room… But we’re OK for now,” a mother of two in the south of Israel told me by voice note.

“Very, very scary. I still cannot believe this is our life… it was VERY close,” a message from a journalist in Tel Aviv said.

“Usually we stay on our floor and don’t go down to the shelter but this time…we realised we had to go down.”

“It was very loud,” lawyer Efrat Eldan Schechter says by WhatsApp message from Ra’anana in central Israel, adding that she believes “it is not the end for tonight”.

“We need to see how it will evolve. It is very scary indeed… but we are strong and confident that our IDF will protect us. Iran just made a huge mistake.”

About an hour after the first message, phones again vibrated with a new alert from the Home Front Command, telling people they could leave shelters and protected areas.

Following the strikes, the IDF spokesperson said there were some hits in central and southern Israel.

Videos later shared on social media showed damage from the missiles in multiple locations, including a large crater in the ground near Tel Aviv.

The Palestinian civil defence authority in the occupied West Bank city of Jericho said a man there died during the Iranian missile barrage.

According to the AFP news agency, which spoke to city governor Hussein Hamayel, the victim was killed by falling rocket debris.

Israeli officials have not reported any serious injuries as a result of Tuesday's air attacks.

“At this stage we don’t identify more launches from Iran. Stay responsible and listen to instructions,” IDF spokesman Daniel Hagari said in a televised address.

Israel says at least 180 missiles were fired, most of them intercepted. It has said there will be “consequences”.

Alice Cuddy