"This was neither a democratic nor a legal referendum," Cavusoglu told Anadolu Agency's Editors' Desk. "It is illegal [according] to Iraq's constitution."
"It is not too late yet. The [President Masoud] Barzani administration could take a step back. If the KRG corrects its mistake, then we can continue with our relations just as we did before the referendum took place."
The regional government, led by President Masoud Barzani, has enjoyed close ties to Ankara and had used a pipeline stretching from northern Iraq to the Turkish Mediterranean port of Ceyhan to export oil, a mainstay of the KRG economy.
However, the independence referendum on Sept. 25 -- held in KRG-controlled areas across northern Iraq, including those disputed with Baghdad -- has threatened the relationship.
According to poll results announced by the KRG, almost 93 percent of registered voters cast ballots in favor of independence.
The referendum had faced sharp opposition from most regional and international actors, many of whom had warned that the poll would only serve to distract from Iraq’s ongoing fight against terrorism and further destabilize the already volatile region.
Cavusoglu also addressed the issue of de-escalation zones in Syria, namely in Idlib.
He described Idlib as a key area in preventing the escalation of tension in the country.
The Turkish foreign minister asserted that coming to a mutual agreement was not enough in Astana, that the implementation of the agreements “needs to be provided”.
"In areas outside the Idlib region, there will be Russia's observers. In certain regions there will be observers of Russia and Iran again. In Idlib and Hama, however, there will be Turkish observers," he said.
He said Turkey, Russia and Iran were taking responsibility as observers to prevent any provocations from both the Bahsar al-Assad regime and the opposition.
The three guarantor states, as well as representatives of the Damascus regime and some opposition factions, had met in Astana in September for a sixth round of talks aimed at ending the six-year conflict.
YPG in Afrin
Turkey, which supports some opposition groups, and Russia and Iran, which back President Bashar al-Assad’s regime, had been holding talks in Kazakhstan since January.
They were seeking to implement lasting cease-fires in areas where fighting has been heaviest between opposition forces and pro-Assad troops.
Asked about Russia’s move to set up a new de-escalation zone unilaterally in the Syrian city of Afrin, Cavusoglu said the YPG’s presence on the other side of Turkey’s border constituted a risk.
Ankara views the PYD and its arm the YPG as the Syrian branches of the PKK terror group.
Three weeks ago, Russian troops positioned themselves, seemingly to create a buffer zone in Afrin between Turkey-backed troops and the YPG.
Turkey's national public broadcaster TRT reported, citing Moscow-based news website Sputnik, that the Russian army had spoken of "de-confliction zone".
“YPG needs to be completely cleared from Afrin," said Cavusoglu. "Turkey will not allow a terror block to be set up in Syria. A terror block on the very other side of our border is a risk for us."
The terrorists, moderate opposition and civilians have to be distinguished “in order to have a good strategy” in fighting terrorist groups, Cavusoglu said.
"Instead of bombarding everywhere randomly,” Cavusoglu said, “the areas with terrorist presence must be targeted.”
The PKK -- listed as a terrorist organization by Turkey, the U.S. and the EU -- resumed its armed campaign against Turkey in July 2015. Since then, it has been responsible for the deaths of more than 1,200 Turkish security personnel and civilians.
New border gate
When asked if any deal is possible with the Iraq's Baghdad on opening a new border gate in Turkey's southeastern Sirnak province, Cavusoglu said it is "technically possible."
On Sept. 25, Turkey's Customs and Trade Minister Bulent Tufenkci refuted local media reports that Turkey blocked access into the country from northern Iraq at the Habur border gate, which is also in Sirnak province.
"There is no closure right now," Tufenkci said, adding that crossings were "strictly controlled for security reasons".
The Customs Minister also said Turkish officials have been working on an "alternative" for Habur border gate, to bypass the KRG and do business directly with central government in Baghdad.
Cavusoglu said a border crossing in Ovakoy is technically possible, but reminded that Iraqi government "needs to provide security and corridor beyond Turkish border."