Russian President Vladimir Putin denounced on Sunday the "brutal attack" at the Coptic Cathedral in Cairo's Abbassiya district, which claimed the lives of 25 worshippers, according to Russian news agency Sputnik.
Putin expressed his "shock and grief," particularly given the high number of women and children among the victims.
The Russian president affirmed his country's commitment to assisting Egypt in its war against terrorism.
At least 49 people were injured after an explosion inside a church attached to the main Coptic Cathedral, according to the health ministry.
Following the attack, Egyptian president Abdel-Fattah El-Sisi announced the country will observe three days of mourning.