Thousands of people attended separate funerals for the dead Sunday.
President Abdel Fattah el-Sissi, meanwhile, chaired a meeting of the Supreme Council of the Armed Forces, which includes the top commanders of the military, to discuss the consequences of the attack, his office said without giving further details.
The extremist group announced its claim of the attack in a statement from their news agency Aamaq. The authenticity of the statement could not be confirmed, but it was released on Telegram, as similar allegations have been in the past.
The attack took place in the town of Qantara in the province of Ismailia, which stretches east from the Suez Canal.
Militants attacked troops at a checkpoint guarding the pumping station and then fled the scene. The military said troops were pursuing the attackers in an isolated area of the northern Sinai Peninsula.
Egypt is fighting an Islamic State-led uprising in Sinai that intensified after the military overthrew an elected but divisive Islamist president in 2013. The militants have carried out dozens of attacks, targeting security forces and Christians.
The pace of militant attacks in Sinai’s main operating theater and elsewhere has dropped to a drip since February 2018, when the military launched a major operation in Sinai as well as parts of the Nile Delta and deserts along the country’s western border with Libya.