Assailants attacked Pakistani soldiers conducting an operation in a restive southwestern province, and three of the soldiers and two insurgents were killed, local officials and the military said Thursday.

The military said in a statement the shootout happened Wednesday in the Baluchistan district of Sui, where the country’s main pipelines of natural gas are located. It was unclear who was behind the attack, but suspicion is likely to fall on local separatist groups who have been blamed for previous such attacks.

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Local officials said an operation to arrest those insurgents who fled after the shootout was underway.

The violence in Sui came hours after five militants attacked a security post in Zhob district in Baluchistan, killing nine soldiers. The military said those five attackers were killed.

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Baluchistan has been the scene of a low-level insurgency by small separatist groups for more than two decades. Baluch nationalists initially wanted a share of the provincial resources, but later they initiated an insurgency for independence.

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Though Pakistan says it has quelled the insurgency, the violence has continued in the province.