Pakistani police officials inspect the site of a suicide bomb attack at a district court in Mardan on September 2, 2016. Pic/AFP

Peshawar: A suicide bomber today blew himself up at crowded Mardan district courts, killing 12 people and wounding 52 others, hours after security forces killed four suicide attackers who tried to storm a Christian neighbourhood in Peshawar in Pakistan's restive Khyber-Pakhtunkhwa province.