The Afghan Taliban will target foreign forces in the country, the group said on Friday, as they announced the start of their spring offensive.“The key objective... will be the foreign forces, their military infrastructure and intelligence, and the elimination of their local mercenaries,” the extremist group said in a statement. “The enemy will be targeted, harassed, killed or captured until they abandon their last posts.” Operation Mansouri -- named after the group’s former leader who was killed in a US drone strike in May 2016 -- will use strategies from “conventional attack to guerrilla operations”, the statement said.Followers were told there can be “suicide attacks, complex attacks and inside attacks” by soldiers or police turning against their peers. The announcement came after the Taliban killed scores of people in a raid on an army base in northern Afghanistan, one of its deadliest assaults on a military installation since the 2001 US-led invasion. Authorities have arrested 35 soldiers who served on the sprawling base, home to the 209th Army Corps, outside the city of Mazar-i-Sharif.The defence ministry says 135 recruits were killed and 64 wounded in the raid. Unofficial sources say the toll was higher.