JERUSALEM — On the same morning that the Israeli military dropped thousands of leaflets on residents in the northern Gaza Strip warning them of an impending military strike and urging them to leave their homes, thousands of Israelis in Tel Aviv, Jerusalem and elsewhere received on their smartphones what initially appeared to be official text messages. First, they warned residents to stay close to bomb shelters, indicating an impending rocket attack from Gaza, and then they warned of suicide bombers who may have infiltrated the public shelters. Here's one of them:

"Message from the Home Command: At 12:16 the IDF will attack in Gaza hard, please make sure you stay as close to a protected area as possible. The message applies to all residents in the country. Please forward this message to other groups urgently be alert and prepared."

The messages are clearly fake – some are in Hebrew and some in English, all with grammatical mistakes, and it's unlikely that Israeli officials would contact the public in such a manner. Plus, the Home Front Command and other official bodies that supposedly sent them have immediately dismissed them as such.

While it is unclear who sent the messages, their appearance over the past six days — since the start of Israel’s military operation in Gaza — marks a new type of psychological warfare that gets right to the heart of everyday life.

The Internet can be used in many ways, said Tal Pavel, an expert on cyberthreats in the Middle East.

"It can be used to send serious information, or the different platforms can be used to spread rumors and disinformation or as part of the fighting," he said. "The goal of the enemy is to scare people, and the more advanced our technology becomes, the more effectively it can be used in this way."

It's unnerving, say those who have received the messages. It takes a few minutes to realize that they are not real and that it's not just you who has been singled out as a target.

"I got the message forwarded to me by several concerned citizens asking me if it was true," said Brachie Sprung, a spokeswoman for the Jerusalem municipality, referring to a text message purportedly sent by the Home Front Command warning residents to stay near a bomb shelter. "Things are so fragile here right now that people are getting worked up about everything they see."

Despite the initial fear, Sprung said that she realized quickly that the message was not from the Home Front Command and that she told people so.

"The Home Front Command know how to work in an organized way, and they know how to reach the public properly if they want to send out a message. They would not do it like this," she said. Instead, officials generally contact the public via television or radio broadcasts.

On Sunday afternoon, immediately after a salvo of rockets fired from Gaza toward the central city of Tel Aviv and rockets fired by militant groups in Lebanon toward the northern city of Haifa, Israelis received another mass text message, this time supposedly from the Shabak, Israel's domestic intelligence agency, also known as the Shin Bet.

"SHABAK: Suicide bomber sneaked to Tel Aviv and center targeting shelters. Beware of strangers in shelters."

On Wednesday, a text message that initially appeared to have been sent by the Israeli newspaper Haaretz said that a "rocket from Gaza hit petrochemical plant in Haifa, huge fire, possible chemical leak, advised to evacuate Haifa." Another said, "Just Now: 25 Israelis killed in missile hit Haifa."

The newspaper later put out a statement saying that it had nothing to do with the messages.

And on Saturday morning, a message on Whatsapp included a map of Israel with a superimposed target on top and a message underneath that said: "The Next Target Be Ready."

"For some reason, people believe something much more deeply if it is written down or broadcast. It just makes it feel more official," said Daniel Eger, a clinical psychologist at Natal, a trauma treatment center in Israel.

Such messages, he said, "make people more afraid," preventing them from carrying out everyday tasks or making simple decisions. He said the trauma center's hotline had seen a 200 percent increase in calls since the hostilities began last week, although there was no way to tell whether the smartphone messages had increased fear.

Psychological warfare via social media platforms is still a relatively new concept, Eger said. "Its something that we will need to address in the future and learn how to tackle."