Egyptian security officials say a roadside bombing has killed three workers contracted to build a security wall in the northern Sinai city of el-Arish.
The officials say another 10 workers were wounded in the explosion on Thursday.
The officials blamed an ISIS affiliate, which is active in that part of the Sinai Peninsula, for the bombing.
The officials spoke on condition of anonymity because they were not authorized to speak to the media.
Suspected ISIS militants on Sunday shot and killed three workers outside their homes in el-Arish.
Egypt has been struggling to contain an insurgency by extremist militants in northern Sinai.
The insurgency intensified after the military’s 2013 ouster of Mohammed Morsi, an elected but divisive extremist president.