“At the time, a terrorist group called Farouq Brigades claimed responsibility for the abduction of Pejman Boyeri and Hassan Hassani along with five other Iranian engineers. Five of them were later released as a result of lengthy negotiations. However, we have had no information about these two individuals,” Press TV quoted Sheibani as saying on Wednesday.

The Iranian ambassador added that efforts to secure the release of the two Iranian electrical engineers had failed given that the terrorist Farouq Brigades disintegrated following the death of its militant commander Abdul Razaq Tlass.

Five of the seven freed Iranian engineers were kidnapped by armed gunmen on their way to the 450-MW power plant in the western Syrian city of Homs on December 21, 2011. The technicians were building the city's Jandar power plant.

The two other released Iranians were abducted one day after the initial kidnapping while on a mission to establish the whereabouts of the missing engineers.

Syria has been gripped by deadly unrest since 2011. Reports indicate that the Western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside the country.

According to the United Nations, more than 100,000 people have been killed and millions displaced in the violence.

HH/HH