Egypt's president says his country has taken "many measures" to step up security at its air and sea ports following the Oct. 31 crash of a Russian airliner and that it will not stop until all sources of concern are removed.

Speaking Thursday at a ceremony marking the signing of an Egyptian-Russian accord to build a nuclear power plant on its Mediterranean coast, Abdel-Fattah el-Sissi says Egypt is willing to cooperate with any party that wants to see improved security at Egyptian ports of entry until every loophole is plugged.

Russia this week said the crash, which killed all 224 people onboard, was caused by an explosive device, backing a claim by the Egyptian affiliate of the extremist Islamic State group that it downed the Metrojet plane.