LAGOS, Nigeria (AP) — Nigeria's police chief is warning that Boko Haram extremists are building bombs in iPads and cellphones and leaving them for people to pick up.

Inspector Gen. Solomon E. Arase issued the warning while announcing five suspects were arraigned Thursday in Abuja High Court in connection with twin bombings in Nigeria's capital that killed 15 people on Oct 2.

Arase said they were arrested in Abuja with "dangerous bombing tools" including high-tech gadgets.

He warned Nigerians to avoid temptation and not pick up abandoned iPads, phones or laptops "as terrorists now use these items in manufacturing bombs."

Nigeria's home-grown extremist group Boko Haram is known for using kidnap victims strapped with explosives in suicide bombings that have killed hundreds in recent months, including in neighboring countries.