Iraninfo-icon's Ministry of Roads and Urban Development has warned companies against shipment of oilinfo-icon products to and from the Iraqi Kurdistan "until further notice," Iranian news agenciesinfo-icon reported on Saturday.

The decision is in line with Tehraninfo-icon's series of measures in response to a referendum held in the semi-autonomous region on possible secession from Iraqinfo-icon which has drawn international criticism.  "Given the recent developments in the region, it is suitable that international transportation companies and drivers active in this field avoid loading and carrying oil products to and from the Iraqi

Kurdistan Region until further notice," a directive by the ministry's Road Maintenance and Transportation Organization said. 

"It should be noted that the consequences of any action in this regard would befall the relevant company," it added.

The transportation is mostly carried out by tanker trucks which take crude oil from the Iraqi Kurdistan to Iran and carry back refined products to the region.

The Iraqi Kurdistan is one of Iran's major trade partners, with annual transactions running to $4 billion a year.

Iran's first concrete reaction to the plebiscite came on Sunday when the country halted flights to northern Iraq and closed its airspace to flights originating in the Kurdish region.

The Islamic Republic has rejected the referendum and asserted its support for Iraq's sovereignty over the entire country, including territories run by the regional Kurdish government.

On Friday, the Iraqi Defense Ministry said it was taking over the control of its borders in the northern Kurdistan region in coordination with Iran and Turkeyinfo-icon.

A ban on international flights into and out of the Iraqi Kurdish region took effect on Friday but the Iraqi central government says local Kurdish authorities should also give back the control of airports and border crossings.