Thousands of people attended separate funerals for the dead on Sunday.
Meanwhile, President Abdel Fattah el-Sisi chaired a meeting of the Supreme Council of the Armed Forces, which includes top military commanders, to discuss the aftermath of the attack, his office said without offering further details.
The extremist group announced its claim of the attack in a statement carried by its Aamaq news agency. The authenticity of the statement could not be verified, but it was made public on Telegram as similar allegations have been made in the past.
The attack took place in the city of Qantara in the province of Ismailia, which extends east of the Suez Canal.
Militants attacked troops at a checkpoint guarding the pumping facility, then fled the scene. The military said troops were chasing the attackers in an isolated area of northern Sinai Peninsula.
Egypt is fighting an Islamic State-led insurgency in Sinai that intensified after the military toppled an elected but divisive Islamist president in 2013. The militants have carried out dozens of attacks, mostly against security forces and Christians.
The pace of militant attacks in Sinai’s main theater of operations and elsewhere has slowed since February 2018, when the military launched an extensive operation in Sinai, as well as parts of the Nile Delta and deserts along the country’s western border. with Libya.