At least 28 people, including many children, were massacred in Egypt on Friday when gunmen ambushed groups of Egyptian Christians traveling along a desert road towards a remote monastery.

The killers lay in wait in the desert outside the city of Minya and slaughtered the occupants of at three different vehicles as they drove towards the monastery of St Samuel the Confessor.

The masked gunmen sprayed bullets into a minibus carrying children from a church group, killing at least six of them, according to Egyptian media. Christian activists said the attackers also boarded a bus and killed the men before robbing the women of their jewelry and phones and leaving Islamist leaflets among the bodies.

Egypt’s interior ministry said 28 people were murdered in total but church officials said they believed the actual death toll may be significantly higher. Another 22 people were wounded.

There was no immediate claim of responsibility for the massacre but suspicion will fall on the Egyptian arm of the Islamic State of Iraq and the Levant (Isil), which has carried out a series of bloody attacks against Christians in the last year.

Suicide bombers killed dozens in a series of strikes on churches in April and December and hundreds of Christians fled the Sinai in March after Isil began a campaign of targeting killings against them.