The authorities in Iraq's self-ruled northern Kurdish region say they've unilaterally started exporting crude oil through Turkey despite objections by the central government in Baghdad.

The Kurds' regional Natural Resources Ministry said in a statement late Wednesday that pumping started in early January.

The oil is being shipped north through a newly constructed pipeline to the Turkish port of Ceyhan, bypassing Baghdad.

The Kurdish ministry has invited companies to participate in a January tender for the 2 million barrels already deposited in Ceyhan. It anticipates an increase in exports to 4 million barrels in February and 6 million barrels in March, with the goal of 10-12 million barrels in December.

Kurds and Arab-led government in Baghdad have been in a long-running dispute over who is in charge of oil exports.