PESHAWAR – Two explosions went off near a police complex in a northwest Pakistani city on Thursday, killing 12 people and wounding 20 others including the local police chief, authorities said. The blasts in Bannu underscored the relentless security threat in Pakistan's regions bordering Afghanistan despite Pakistani army offensives and US missile strikes aimed at al-Qaeda and Taliban fighters. The second blast came as rescuers responded to the first – a militant tactic seen before in Pakistan, but not often. Insurgents have carried out numerous attacks on security forces over the past several years to undermine the public's confidence in the alreay-weak state.