An Egyptian general was killed by militants on Friday near his home in North Sinai, the military said, the second soldier of his rank to be shot dead in as many weeks.
Islamic State claimed responsibility for the attack, in which gunmen opened fire on Brigadier General Hesham Mahmoud Abualazm from a moving car in Arish city, North Sinai's provincial capital.
Abualazm, 47, died instantly. He was on a visit to Arish, where he owned a house, and does not serve in Sinai, security sources said.
Islamic State claimed responsibility via its news agency Amaq.
Hundreds of soldiers and police have been killed in an Islamist insurgency led by the jihadist group in the rugged and thinly populated Sinai Peninsula.
Attacks have been stepped up since the military overthrew President Mohamed Mursi of the Muslim Brotherhood, Egypt's oldest Islamist movement, in mid-2013 following mass protests against his rule.
A new group calling itself Louwaa al-Thawra, or the Revolution Brigade, claimed responsibility for an attack on Oct. 22 in which another general was killed in the same way as Abualazm.
Another senior military officer and a soldier were killed on Saturday in North Sinai in a roadside explosion.
Egyptian authorities said earlier on Friday they had arrested leaders and members of Louwaa al-Thawra and another recently emerged militant group, the Hasam Movement, along with weapons and explosives.
Authorities also said they had proof the organisations had been set up by the Brotherhood, which says it is a non-violent movement.
Judges, policemen and senior officials have increasingly been targeted by radical Islamists angered by hefty prison sentences imposed on members of the now-outlawed Brotherhood.