Three Iranian security personnel were killed by militants in a cross-border attack on the frontier with Pakistan on Tuesday, according to Iran’s Revolutionary Guards. An Iranian police officer was killed in an ambush at a border post in the city of Mirjaveh in Sistan-Baluchestan province, while two other soldiers died when their vehicle was hit by an improvised explosive device (IED), Reuters reported, citing the Guards. The statement, posted on state media, said three people described as terrorists were killed by Iranian security in a “firm and timely response.” Sistan-Baluchestan province in southeastern Iran has long been plagued by unrest from both drug-smuggling gangs and separatist militants. The population of the province is predominantly Sunni Muslim, while the majority of Iranians are Shiites.