Buckingham Palace said the King was "extremely concerned" and his thoughts and prayers were with all who were suffering.
Israel has vowed unprecedented retaliation against the Palestinian militant group Hamas after its terrorists stormed through the Gaza border on Saturday.
They went on to kill hundreds, including babies, in their homes, on streets and at a music festival.
The Jewish state has launched a barrage of air strikes on the territory and stopped food, water, fuel and medicine supplies.
The violence has already claimed at least 2,100 lives on both sides, with fears it could escalate further.
A Palace spokesman said: "This is a situation His Majesty is extremely concerned about and he has asked to be kept actively updated. His thoughts and prayers are with all of those suffering, particularly those who have lost loved ones, but also those actively involved as we speak."
He added: "His Majesty is appalled by and condemns the barbaric acts of terrorism in Israel."
Distressed
The King, 74, spoke to Israel's president, Isaac Herzog, and King Abdullah of Jordan yesterday, to express condolences and try to encourage key Middle East players to avoid a wider confrontation.
Sources close to the King stressed his lifelong efforts to encourage inter-faith and community dialogue, peace and understanding, both nationally and internationally.
He is supported by Prince William, 41, who visited the Holy Land in 2018, and wife Kate.
هذه القصة مأخوذة من طبعة October 12, 2023 من Daily Express.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك ? تسجيل الدخول
هذه القصة مأخوذة من طبعة October 12, 2023 من Daily Express.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك? تسجيل الدخول
'Now Amie can rest in peace'...student is guilty of stab murder
THE wife of a woman butchered on a beach yesterday said she can now be at peace after a criminology student was convicted of murdering her in a stabbing frenzy.
King's brother will stay away from Palace after links to China 'spy' emerged PRINCE ANDREW FROZEN OUT OF ROYAL S XMAS LUNCH
PRINCE Andrew has found himself out in the cold this Christmas as he will not join any Royal Family gatherings.
Drink deaths jump by 42% in five years
MEDICAL experts want urgent action to tackle a \"catastrophic\" rise in deaths caused by drinking.
Ukraine's humble legend giving hope to soldiers fighting on the frontline
USYK REVEALS HOW HIS TITLE WIN WAS RELAYED TO TROOPS
BACK-UP KEEPER IS ONE KELL OF A JOB
Slot knows being Alisson's No.2 is tough for Caoimhin
Howe makes winning a trophy talk of the Toon
EDDIE EMBRACING THE IDEA SQUAD CAN END LONG WAIT FOR GLORY
Bell strikes as feeble hosts fall apart
ENGLAND skittled South Africa for just 64 as they powered to a 286-run win in the one-off Test in Bloemfontein.
Stokes vows to return stronger than ever before
INJURY WON'T HOLD SKIPPER BACK
Running a chippy fried Price's brain
FOCUS NOW BACK ON SPORT
All coming together for rising star Jones
UP-AND-COMING trainer Jack Jones will have all his horses under the same roof from the new year after completing a deal to buy Rae Guest's Newmarket stables.