Police said four officers were killed and seven were wounded when their patrol unit was attacked in Helmand province late Saturday, CNN reported Sunday.

The officers were monitoring a market in the Gerishk district at the time of the attack, District Police Chief Khair Mohammad Sheja said. Two militants were taken into police custody Sunday.

Four more officers were killed in a separate attack on their unit in Kandahar province Saturday.

The officers were destroying poppy fields when they came under fire, Police Chief Sayed Agha Saqib said.

An unknown number of militants were killed by police in a subsequent battle, CNN reported.