Authorities in Pakistan said Saturday that at least 18 soldiers were killed in an overnight insurgent attack in southwestern Baluchistan province, marking one of the deadliest days for security forces in recent months.

A military statement said that the casualties occurred in the Kalat district Friday night, when “terrorists attempted to establish roadblocks” in the area, and that security forces promptly responded to what was labeled "a cowardly act of terrorism.”

The military said at least 12 assailants were killed in the ensuing gun battles.

Pakistani Prime Minister Shehbaz Sharif’s office in Islamabad said in a statement that he strongly condemned the attack on security forces.

A series of security operations has been launched throughout Balochistan since the overnight attack, which killed at least 11 "terrorists" and destroyed their hideouts on Saturday, according to an army declaration.

“The sanitization operations will continue until perpetrators and facilitators of the heinous and cowardly act are brought to justice,” it said.

The outlawed Baloch Liberation Army, or BLA, reportedly claimed responsibility for the attack.