Speaking to a press conference in Istanbul, Erdogan said the referendum was null and void to Turkey.
“Regardless of the results, the referendum, which is not in conformity with the current law in Iraq, is null and void for us, we call it illegitimate,” Erdogan said.
He reiterated Turkey’s support for Iraq’s territorial integrity and social unity, adding, “And we will work to ensure that.”
“We are taking all kind of steps in northern Iraq, particularity on political, economic, commercial and security issues,” he said.
He pointed to the ongoing military drill at Turkey's border with northern Iraq, adding that more measures would be announced soon.
“At the same time, the [Turkish] Air Force is in the same situation and only permits passage as far as the Iraqi border," he said.
"We will immediately announce other measures and steps taken this week.”
Erdogan also underlined that the border crossing to and from northern Iraq would be blocked.
"Let’s see how and where the northern Iraq local authority sells petroleum," he said, adding that Turkey is the only way for northern Iraq’s oil to reach world markets.
“The [oil] valve is ours. If we shut off the valve, it will be over.”
He said the KRG must step back from its referendum decision otherwise “we will continue to take steps with determination."
Monday's non-binding referendum will see voters in northern Iraqi Kurdish Regional Government (KRG)-held areas, including areas disputed between Erbil and Baghdad, vote on seceding from Iraq.
Baghdad, Turkey, Iran and the UN have all spoken out against the poll, saying it will only distract from the ongoing fight against Daesh and further destabilize the region.
Iraq’s central government has threatened to intervene militarily if the vote leads to violence.
KRG head Massoud Barzani has said a “Yes” win would not result in an automatic declaration of independence but would simply lead to further negotiations with Baghdad.
AA/MNA