Iran hanged 16 prisoners Saturday following an overnight attack in which at least 14 border guards were killed near the country’s boundary with Pakistan, an official said. The executed prisoners were believed to be part of the same separatist group as those involved in the cross-border attack, Iranian authorities said.

"These individuals were executed this Saturday morning in response to the terrorist action of last evening at Saravan and the martyrdom of the border guards," Iranian state television quoted an Iranian prosecutor as saying.

The people hanged had been arrested before the attack, and the prosecutor gave no details of any trial proceedings.

Iran's state TV reported earlier Saturday that at least 14 Iranian border guards were killed in clashes with "armed bandits." The report did not provide any details about the identity of those involved.

Details on the number of border guards killed were also unclear, with Reuters reporting 20 killed and Iranian State TV suggesting the number was closer to 17. A deputy governor of Saravan, the town near where the clashes occurred, told state television that the attackers also captured six border guards.

"The attackers, who saw that conditions were unsafe for their actions, retreated to” the Pakistani side of the border after the clash, Rajab-Ali Sheikhzadeh, a provincial official, told the ISNA news agency.

Al Jazeera's Soraya Lennie, reporting from Tehran, said the Iranian government was blaming a separatist group, known as Jaish Ul Adl (Party of Justice), for the attack on its border guards.

Our correspondent said that the group was vehemently anti-Shia, and that the Iranian government had in the past pressured the Pakistan government to crack down on the group's activities.

The area has a history of unrest, with the mainly Sunni Muslim population complaining of discrimination at the hands of Iran's Shia Muslim authorities.

Security forces have also fought drug traffickers in the area near the borders with Pakistan and Afghanistan.

Al Jazeera and wire services