- More than 20,000 Palestinians were killed and more than 52,600 others were wounded as a result of Israeli airstrikes, according to the Palestinian Ministry of Health;
- The Israel army announced deaths of four of its servicemen in the Gaza Strip;
- On December 21, clashes between Palestinian and Israeli forces continued in Khan Yunis city;
- On December 21, clashes between Palestinian and Israeli forces were reported in the east of Maghazi;
- On December 21, clashes between Palestinian and Israeli forces continued in Shujaiyah;
- On December 21, clashes between Palestinian and Israeli forces continued in Jabalia.
- On December 21, artillery duels and clashes between Hezbollah and Israeli forces continued in the Lebanese border area;
- On December 21, Hezbollah attacked Israeli positions in Shebaa farms with several rockets and suicide drones;
- On December 21, Hezbollah artillery shelled Avivim outpost;
- On December 21, Hezbollah artillery shelled Dovev;
- On December 21, Israeli artillery shelled the area of Tairharfa;
- On December 21, Israeli artillery shelled the area of Naqoura;
- On December 21, Israeli warplanes struck the Kfarkala area.
- Israeli forces murdered a young Palestinian near Bethlehem;
- Palestinian groups fired dozens of rockets at Tal Aviv;
- Israeli forces raided the town of Jalma near Jenin;
- Since the beginning of the fighting on October 7th, more than 4,600 Palestinians have been arrested by the Israeli army in the West Bank.