Iran's major oil transferring pipeline in southwestern Iran exploded on Friday morning, the semi- official Mehr news agency reported.

For unknown reasons, the oil transferring pipeline from Qalehnar to Ahvaz oil establishments, one of the county's major oil pipelines, exploded and caught fire on Friday morning, said the report.

The explosion caused the flames to rose to 40 meters high and the fire to spread to more than 300 hundred meters away from the pipeline, said Mehr.

Currently, the emergency, operational and the technical teams of Iran's Southern Oil National Company have controlled the fire in the exploded pipeline and it is expected the repairs to begin within the following hours.

After the explosion, the technical workers started to evacuate crude from the pipeline and the production units linked to the pipeline stopped their routine function, according to Mehr.

The 30-inch pipeline, which has the capacity of transferring some 3,000 to 4,000 barrels of oil on the daily basis, transfers the crude from Qalehnar oil wells in Iran's Western Lorestan province to Ahvaz oil establishments in southwestern Khouzestan province, said the report.

The officials have started investigations into the incident.

Last week, an explosion hit Iran's oil-transferring pipeline to Turkey in northwestern Iran. Iran blamed the Kurdish rebels for the blast.