An Iranian man was hanged on Sunday apparently by the parents of his victim whom he murdered when he was a minor, the official IRNA news agency said.

Behnoud Shojaie had been convicted of stabbing to death 17-year-old Ehsan Nasrollahi during a fight in August 2005 when he himself was aged 17, IRNA reported.

Shojaie was "said to have been hanged by the victim's parents" in Tehran's notorious Evin prison, said the agency.

Former Iran judiciary chief Ayatollah Mahmoud Hashemi Shahroudi had agreed in June last year to suspend Shojaie's death sentence to give the victim's family a chance to pardon him under Islamic sharia law.

Shojaie's case drew international attention and several domestic human rights groups also strongly called for halting the execution.

The latest hanging brings to at least 231 the number of people executed in the Islamic republic so far this year, according to an AFP count based on news reports.

In 2008, Iran executed 246 people, second only to China.

Tehran says the death penalty is a necessary tool for maintaining public security and is applied only after exhaustive judicial proceedings.

Murder, rape, armed robbery, drug trafficking and adultery are all punishable by death in Iran.