ARISH, Egypt, July 26 (Xinhua) -- At least three civilians, including two children, were killed and nine others injured on Saturday as a mortar round hit two houses of Sheikh Zuweid city in Egypt's North Sinai province bordering Israel, according to a security source.
"The mortar round was launched by extremist militant groups and mistakenly hit two houses at al-Joura town south of Sheikh Zuweid, " the source added, noting the injured were taken to Arish Hospital for treatment.
At least 26 extremists were killed in military raids that continued from Friday afternoon until Saturday evening at Sheikh Zuweid in response to the killing of two police and military officers by gunmen on Friday.
Military spokesman Mohamed Samir said the forces destroyed 36 houses and 40 huts used as hiding places for extremists in the restive peninsula.
According to the source, the extremists belonged to the Sinai- based al-Qaida-inspired Ansar Bayt al-Maqdis group, which has claimed responsibility for a number of deadly terrorist attacks since the ouster of former President Mohamed Morsi last year.
Last week, militants killed 22 military men at a checkpoint in Al-Wadi al-Gadid province, about 500 km southwest of the capital Cairo.
Extremist self-proclaimed Islamist groups, which refer to Morsi 's overthrow as "a military coup," say their attacks were in retaliation for the harsh security crackdown on the major sit-ins of Morsi's supporters in August 2013, which left at least 1,000 killed and thousands more arrested.
On Saturday, the procession referred 20 suspect members of a similar extremist group named Ajnad Misr (Soldiers of Egypt) to criminal court over killing six police officers and a civilian in a string of attacks in Cairo late June.