NAIROBI, Kenya (AP) — A senior Kenyan police official says four policemen and four children were killed when a lorry they were traveling in ran over an improvised bomb in Kenya's southern coastal area.

Noah Mwivanda, a senior police officer in Lamu County, said Tuesday the explosion took place in Kiunga town.

This incident increases to 46 the death toll from homemade explosives planted by suspected al-Shabab extremists from Somalia in the last three months. The majority of fatalities have been policemen. Al-Shabab has carried out more than 100 attacks on Kenya since 2011, saying they are retribution for the country sending troops to Somalia to fight the insurgents.

Areas of Lamu and Mandera counties, near the Kenya-Somali border, have been hardest hit by al-Shabab attacks in recent years.