KAMPALA, Uganda (AP) — Several Kenyan police officers were killed in an attack Monday night by suspected Somali militants in the northeastern Garissa county, where 148 students were massacred last month, local media reported. The Islamic extremist group al-Shabab has carried out several attacks in Kenya in retaliation for Kenya's military involvement in Somalia, where Kenyan troops are part of an African Union force bolstering the Western-backed central government.