The messages were dropped by Israeli aircraft amid the waves of air strikes targeting Gaza, that Hamas health officials said have killed more than 5,000 people.

"If you want a better future for yourself and your children, do the right thing and send us safe and useful information about kidnapped people in your area," said the Arabic message on leaflets seen by AFP.

"The Israeli army promises to do everything to preserve your security and that of your homes, as well as a financial reward," the leaflet added. "We guarantee you total discretion."

The document provided a telephone number along with details regarding Telegram, Whatsapp and Signal messaging services, where information could be sent about the hostages.

The Israeli army confirmed the launch of the effort.

"As part of the extensive efforts to free the Israeli and foreign national hostages held by the Hamas terrorist organization in Gaza, the (army) today used multiple channels to communicate with the residents of Gaza and ask for information about the hostages," the army said in a statement.

More than 220 Israelis, dual nationals and foreigners were kidnapped by Hamas militants during their shock attack on southern Israel on October 7 which killed more than 1,400 people, according to Israeli officials.