ISLAMABAD, Pakistan (CNN) -- At least 18 officers were killed Sunday in a suicide attack at a police training center in Mingora in Pakistan's northwest, officials said.
The attack also wounded 12 others, said military spokesman Major Pir Mushtaq.
The attacker jumped over a wall at the compound and blew himself up as about 50 to 75 newly-recruited officers were training, said Mian Iftikhar Hussain, the information minister of the North West Frontier Province.
Authorities recovered the suicide bomber's head, Mushtaq said.
Mingora is the largest city and the gateway into the province's Swat Valley, where Pakistani military are fighting Taliban militants for control.
On Saturday, security officials said the army killed six militants and wounded several others in an operation to destroy the militants' base of attacks.
The army launched the operation after intelligence information and reports from locals about the presence of suicide attackers and terrorism masterminds close to the Valley town of Charbagh.
Militants had been using a safe area there to launch attacks in other Valley towns, including Mingora.
CNN's Samson Desta contributed to this report.