"In an operation around the town on Dehgolan, the police was able to kill one person and arrested another one," official IRNA news agency quoted the deputy governor general of Kordestan province, Iraj Hasanzadeh, as saying.

"The person arrested was wounded during the operation and he told us that he and his comrade were behind the killing of the four forest guards," earlier this month, he said.

Hasanzadeh said the pair were members of a "hardline religious group."

"The members of this group are more than two and there is a search underway to find the others," he said.

Hasanzadeh did not identify the group but, in an other dispatch, Mehr news agency quoted him saying they are "Salafis (hardline Sunni Muslims)."

Environmental official Kheyrollah Moradi said last Saturday that four Iranian border guards were killed and described the murder as a "terrorist act."

The men had gone missing on Friday and their bodies found seven hours later in the Dooshan area of the western province of Kordestan, he said.

Western Iran, home to a significant Kurdish population, has been the scene of deadly clashes for years between security forces and Kurdish rebel groups operating from bases in neighbouring Iraq.

In September 2010, a deadly bombing hit a military parade in the western city of Mahabad in Kordestan which is mainly Sunnis, killing 12 people and wounding at least 81.