Hamas militants seized about 120 hostages when they unleashed a surprise attack on Israel and gunned down more than 1,300 people, including civilians, on October 7, the Israeli army said.

Here is what we know about the hostages and the efforts being made to free them.

Is there proof of life?

After a week of uncertainty, the Israeli army said Hamas had taken at least 120 people captive, including civilians and soldiers, and estimated their total number could be 150, without being certain if they are alive or dead.

The hostages include Israeli soldiers, women, children, and the elderly, as well as foreign workers and people with dual nationality.

Evidence of the kidnappings has come from images taken and published by Hamas both during and after the attack. The data from some of the Israelis' phones showed they were on Palestinian territory.

Hamas, which threatened to kill the hostages in response to any unannounced Israeli strikes on civilian targets, said 22 of them have been killed in Israeli bombardment, although this cannot be verified. Over 2,200 people have been killed in Israel's strikes on Gaza since last week.

How is Israel responding?

Israel's government has tapped Gal Hirsch, a former general embroiled in a corruption scandal, to coordinate the hostage crisis, an appointment that was condemned by observers.

An FBI negotiator is also on-site, with several US citizens among those Hamas is holding.

On the ground, Israeli forces made forays into Gaza on Friday night "in search of evidence to locate the hostages", whether they are alive or dead.

Israel's Sayeret Matkal elite commando unit is thought to be best placed to carry out any incursion to extract the hostages.

They will face a hard task to locate them, however, as Hamas is known to operate with a system of decentralized cells.

Gershon Baskin, a negotiator for the release of Israeli soldier Gilad Shalit in 2011, said "Any Hamas fighter who hands over a hostage at the border must be guaranteed amnesty and passage to the West Bank".

Are there any international efforts to free them?

So far there has been no word of any international efforts to secure their release.

In addition to likely mediation by Egypt — the usual negotiator between Israel and Hamas — Turkish President Recep Tayyip Erdogan and the International Committee of the Red Cross claim to be holding talks with the militant group.

"As a neutral intermediary we stand ready to conduct humanitarian visits; facilitate communication between hostages and family members; and facilitate any eventual release," Fabrizio Carboni, the ICRC's regional director for the Near and Middle East, said on Thursday.