Gunmen from the Palestinian group Hamas took at least 200 hostages and killed about 1,400 people during an Oct. 7 dawn raid carried out from the Gaza Strip on communities and military bases in southern Israel.
Israel has responded by pounding Gaza with air strikes, killing thousands, and has said it will act to free the hostages while wiping out Hamas.
Israel has amassed tanks and troops near the perimeter of the enclave and called on Palestinians to evacuate the north of Gaza before an expected ground invasion.
Hamas has suggested the hostages could be swapped for approximately 6,000 Palestinians held in Israeli prisons.
In 2011, Israel was criticized by some of its citizens for swapping 1,027 Palestinian prisoners to win the release of one Israeli soldier.
Israel has said that there will be no end to the blockade of the enclave without freedom for Israeli hostages.
The Rafah crossing between Egypt and Gaza is expected to open for the delivery of limited amounts of aid from Friday.
HOW MANY HOSTAGES ARE THERE?
An estimated 200 people, including 30 minors and young children and 20 people over the age of 60, are being held hostage in Gaza, Israel's public broadcaster Kan said on Thursday, citing military sources.
Hamas says it has between 200 and 250. It said more than 20 hostages have been killed by Israeli air strikes, but has not given any further details.
WHERE ARE THE HOSTAGES?
Israel says the hostages were taken to Gaza but their exact whereabouts within the enclave are unknown, making their rescue more complicated. It is believed many could be held in the warren of tunnels under Gaza that Israeli troops call the "Gaza Metro".
Hamas on Monday released a video of Mia Schem, a 21-year-old French-Israeli woman captured at a dance party. In the video, she was shown being treated for an injury to her arm by an unidentified medical worker.
WHAT NATIONALITIES ARE THE HOSTAGES?
The hostages include people from dozens of countries, while many also have Israeli citizenship.
Twenty or more Americans are missing, U.S. national security adviser Jake Sullivan said on Tuesday, adding that he could not say how many of those were being held hostage. Republican Senator Jim Risch told reporters on Tuesday that 10 of the hostages were Americans.
Thailand says 14 of its citizens are being held. Eight Germans are among the hostages, about half of whom were seized at a kibbutz, according to local media.
Argentine President Alberto Fernandez said in a video call with families that 16 of his countrymen were being held.
At least nine British nationals have been killed and seven missing, Prime Minister Rishi Sunak's spokesperson said. During a trip to Israel on Thursday, Sunak met with the families of two of the missing who are believed to have been taken hostage and held in Gaza.
France has not said exactly how many of its citizens are held in Gaza, although there are seven unaccounted for after the attacks, of which some are being held hostage.
Ofir Engel, an 18-year-old Dutch national, was kidnapped from Kibbutz Be'eri and taken to Gaza, according to the Dutch government.
Portugal said it assumes that four Portuguese-Israelis who are missing have been taken hostage. Israeli-Chilean Dafna Garcovich was taken hostage with her Spanish husband Ivan Illaramendi, her father said. Italy says two dual Italian-Israeli nationals are missing, presumed kidnapped.
Hamas's armed wing said on Oct. 16 that kidnapped non-Israelis were "guests" who would be released "when circumstances on the ground allow."
WHAT HAVE GOVERNMENTS SAID THEY ARE DOING ABOUT THEM?
Israeli Prime Minister Benjamin Netanyahu has appointed a retired general, Gal Hirsch, as Israel's coordinator on hostages and missing persons.
Turkey is also talking with Hamas to secure the release of foreigners, civilians and children, Foreign Minister Hakan Fidan said on Tuesday. He told state-run Andalou news agency that countries including the U.S. and Germany have asked for help from Turkey on winning the release of their citizens.
U.S. President Joe Biden said his administration is "workin’ like hell" to find American hostages held by Hamas. The U.S. has sent a small team of special operations forces to Israel to help with intelligence and planning for any eventual operations to rescue the hostages.
Britain's Sunak has said his government is talking to partners in the region to try and help secure the return of hostages.
Argentina's Fernandez said his government was talking with Israeli intelligence forces to locate Argentine hostages.
Germany has opened an investigation into members of Hamas for suspected murder, manslaughter and hostage-taking. Under German law, prosecutors are compelled to investigate suspected crimes abroad if they involve German citizens.
WHAT HAVE FAMILIES OF HOSTAGES SAID?
Families of missing Franco-Israeli citizens urged French President Emmanuel Macron to help locate their missing relatives.
The families of German hostages said they will hold a rally in Berlin on Sunday to call for their relatives' release after meeting with German Chancellor Olaf Scholz in Tel Aviv.
U.S. citizens in Tel Aviv urged Biden to use all resources to locate and rescue their kidnapped relatives.
(This story has been refiled to replace the word 'now' with 'know' in the headline)
