The Iraq government called on the international community to cease importing crude oil from the autonomous region controlled by the Kurdistan Regional Government, Reuters reports.

In a statement from the prime minister’s office, the government asked foreign buyers to purchase directly from the central government, according to Reuters.

The statement was released on Sunday, the day before the KRG’s independence referendum, in an apparent attempt to put pressure on the regional government.

Currently the KRG exports oil through a pipeline to the Turkish coast, Reuters reports. Crude exports from the autonomous region have long soured relationships between the KRG and the central government.

Turkey, itself unhappy with the KRG’s referendum, has indicated that it might cut off Kurdish exports through the pipeline, Reuters reports.

Last month, the central government announced plans to explore a pipeline from Kirkuk, a province largely controlled by the KRG, to Iran—a move, if carried out, that will deprive the KRG of oil revenues that it currently enjoys.

The KRG produces approximately 650,000 barrels per day (b/d) of oil. The regional government plans to increase this amount to 1 million b/d by the end of 2019, according to Reuters.

Last week Reuters reported that Rosneft, a Russian oil firm, had agreed to invest $1 billion in a natural gas pipeline to export the KRG’s natural gas.