Gunman ambushed and killed an Iranian state prosecutor Wednesday in a restive southeastern region near the Pakistani border, reports said, less than two weeks ago after militants killed 14 border guards and prisoners described as "rebels" were later hanged in apparent reprisal.
It was not immediately clear whether the latest killing was linked to the unrest in Sistan-Baluchistan province, which includes clashes with drug smugglers and sporadic battles with an armed faction that claims to fight on behalf of Iran's Sunni minority.
But state radio said the slain prosecutor, Mousa Nouri, has been considered one of the toughest against suspected opium and other drug networks that use routes leading from Pakistan and Afghanistan over the rugged hills and deserts.
For years, Iran has built up military and police forces in the area to counter the traffickers and a small, but increasingly violent, insurgency by Sunni groups fighting Iran's Shiite-led authorities.
The minority Sunni Muslim population in southeastern Iran has long claimed they face discrimination in Shiite Iran and are under increased surveillance from authorities because of ethnic ties to the Baluch community in Pakistan, where a militant group known as Jundallah, or Soldiers of God, has operated for years.
A separation faction calling itself Jaish al-Adl, or Army of Justice, claimed it carried out the Oct. 25 attack that killed 14 border guards. The group later vowed to avenge the hangings of 16 prisoners suspected of militant links.
The semi-official Fars news agency said Nouri was gunned down in the town of Zabol near the Pakistan border.
Another news agency, ISNA, quoted the region's judiciary chief, Ebrahim Hamidi, as claiming the slaying was not connected to the October hangings.
In December 2010, Jundallah claimed responsibility for killing 39 Shiite worshippers at a mosque in an Iranian border town. Later that month, Iran hanged 11 men who authorities said were members of Jundallah.