Baghdad-Iraq's semi-autonomous Kurdistan Region is holding an independence referendum in the face of strong objections from the central government in Baghdad and in defiance of urgent calls from the worldwide community to scrap the vote.
Kousha noted that the vote on independence is not just a domestic issue, but could spark further fighting among Kurds and the central governments in Syria and Turkey, which could lead to a broader regional war.
The referendum has raised alarm in Iraq's neighbours - Turkey, Iran and Syria - over concerns it could encourage their own Kurdish minorities to break away.
He said Turkey would no longer provide "military training support for the [Kurdish] Peshmerga forces", adding Ankara would from now on be engaging primarily with the Baghdad administration.
"After this, let's see through which channels the northern Iraqi regional government will send its oil, or where it will sell it", Erdogan said in Istanbul.
"An assistant to the Syrian foreign minister told the pro-government Syrian newspaper al-Watan that what is happening in Iraq "is a product of American policies that aim to fragment the region's countries and create conflict between its parts".
"At the request of the Iraqi government, we have closed our land and air borders", he said.
Erdogan said traffic was only being allowed to cross from the Turkish side of the border into Kurdish areas of Iraq. The United States has strongly opposed the move, saying it could destabilize the region. They have also argued over the sharing of oil revenues, with the Kurds exporting through a Turkish pipeline over objections from Baghdad.
"We stress again that we will take all measures arising from global law and the Turkish parliament's authority in the face of every kind of threat to our national security in Iraq generally", it said.