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Dozens of foreign nationals are feared dead in Israel following the terror strikes by Hamas at the weekend.
An estimated 3,000 rockets were fired, leaving more than 700 dead and thousands injured in the attack.
Nine Americans have been killed in the war between Israel and Gaza, and several more are unaccounted for, the State Department said on Monday. In Britain, more than 10 people are believed to have been killed or remain missing.
The German foreign ministry has confirmed several dual German-Israeli nationals have been kidnapped.
The mother of 22-year-old Shani Louk told German news website Der Spiegel she recognised her daughter in videos circulating online of a woman lying face down in the back of a pickup lorry in Gaza with armed men seated around her.
On Monday, France said eight of its nationals were missing and confirmed two have been killed.
"France regrets the tragic death of a second French national, who fell victim to Hamas's terrorist attacks against Israel," the ministry said.
Thailand said 12 of its nationals have been killed and 11 are missing, Nepal said 10 of its citizens are dead. Two Ukrainians, a man from Cambodia and a Canadian have also lost their lives.
An Irish-Israeli woman, named as 22-year-old Kim Damti, who was attending the music festival, has been confirmed missing by the Irish government.
Two other British men, Bernard Cowan and Dan Darlington, have been identified by family members on social media as having been killed in the attack.
Photographer Mr Darlington has been living in Germany and was visiting Israel with his friend Carolin Bohl.
Her sister Anja Pasquesi posted on Instagram: "Today we learnt from Carolin's friend on the ground in Kibbutz Nir Oz in Israel that she and her friend Danny were killed in a terrorist attack yesterday.
"We are broken and are working to cope with this unimaginable tragedy. We send our deepest thanks to those who made such an effort today to help find her and provide information and contacts. Please give us some time and space to remember our sweet angel Caro and her beloved friend Danny.
"Our hearts are broken forever. Rest easy sweet Caro. My angel sister is in heaven. She was 22 and was killed by Hamas terrorists. We are absolutely heart-broken."
Anja's husband and Carolin's brother-in-law, Sam Pasquesi, wrote on Instagram: "While we haven't got official notification from the governments of Israel, Germany or UK, we have reliable information from the ground in Israel that our beloved Caro and her dear friend Danny were killed in a terrorist Hamas raid.
"We are so thankful to family, friends, and strangers for the aid in providing such expedient information, press and government contacts, hopes, prayers and comfort. We will now focus on coping with this tragedy and ask for some time and space to come to terms with it."
Jake Marlowe, 26, who moved to Israel from Britain two years ago, is believed to have been taken hostage while providing security at a music festival.
His mother Lisa told The Jewish News that he called her "to say all these rockets were flying over," and then later to tell her "signal very bad, everything OK, will keep you updated I promise you" before she lost contact with him.
British man Nathanel Young, 20, who was serving in the Israeli army, died fighting Hamas, his family said on Sunday.
On Monday, foreign minister James Cleverly said he would not speculate on the number of British or dual nationals in the area.
"The nature of Israeli citizenship means that there are a significant number of dual British-Israeli nationals, many of whom will have made their permanent home in Israel, many of whom will be serving with the Israeli defence force," he said.
"So it's not possible for us to give numbers and I do not intend to speculate."
The Foreign Office told The National: "We do not comment on individual cases but we are in contact and are assisting families in Israel and the occupied Palestinian territories."
French officials were similarly scrambling to respond to the crisis.
"We are continuing our efforts to clarify the situations of those of our nationals who remain unaccounted for," a spokesman said.
"At least eight French people are believed to be missing, dead or taken hostage by Hamas," French politician Meyer Habib said in a social media post.
"Paris should hold Hamas directly responsible for (hostages') safety and use every means to secure their release."
Mr Habib said that he had spoken to the father of 26-year-old Avidan T from Bordeaux, who lives in Israel.
The father "confirmed to me that, as we feared, this young Frenchman... has indeed been taken hostage," he wrote.
Mr Habib said Avidan was one of the revellers at a desert rave in southern Israel hit in a Hamas attack that killed as many as 250 people.
The foreign ministry said Monday that almost 62,000 French nationals were registered with the consulate-general in Tel Aviv, with a further 25,000 in Jerusalem.
Many French travellers were also present in Israel at the time of the attacks, it added.
Nine Americans have also been killed and many more are missing.
"At this time, we can confirm the deaths of nine US citizens," State Department spokesperson Matthew Miller said in a statement.
"We can confirm that there are unaccounted-for US citizens, and we are working with our Israeli partners to determine their whereabouts."