Turkey has accused the head of Iraq's autonomous Kurdish region of "treachery" for pursuing an independence referendum, while the Iraqi government has threatened to ban flights into Kurdish regional airports.
The rhetoric from both Ankara and Baghdad on September 26 ratcheted up pressure on the Kurdish region following the referendum vote a day earlier.
Initial results showed 72 percent of eligible voters had taken part and an overwhelming majority, possibly over 90 percent, had said "Yes," according to Kurdish television Rudaw. Final results were expected September 27.
Some 30 million ethnic Kurds live in Iraq, Iran, Turkey, and Syria, and regional governments fear the spread of separatism from northern Iraq to their own Kurdish populations.
In a speech in Ankara on September 26, Turkish President Recep Tayyip Erdogan warned that Turkey blocks Kurdish trucks from crossing the border, and he said all options, including economic and military, were on the table.
Turkey, in particular, has seen the vote as a threat to its national security and fears it will inflame separatism among its own Kurdish population.
"Until the very last moment, we weren't expecting Barzani to make such a mistake as holding the referendum, apparently we were wrong," Erdogan said, referring to Kurdistan region President Masud Barzani.
"This referendum decision, which has been taken without any consultation, is treachery," Erdogan said, threatening again to cut off the pipeline that carries oil from northern Iraq to the outside world.
Erdogan's remarks came after the Iraqi government also ruled out talks on possible secession for Kurdish-held parts of northern Iraq.
"We are not ready to discuss or have a dialogue about the results of the referendum because it is unconstitutional," Iraqi Prime Minister Haidar al-Abadi said in a speech.
Abadi also gave the Kurdish authorities until September 29 to hand over control of its airports or face an international air embargo.
Just hours after polls closed on September 25, the Iraqi Defense Ministry announced the launch of "large-scale" joint military exercises with Turkey.
In Tehran, the Iranian parliament announced it would hold a closed-door meeting on the referendum on September 27.
WATCH: Iraq's Kurds Vote In Independence Referendum
Meanwhile, in northwestern Iran, thousands attended demonstrations in support of the referendum in the Kurdish-majority cities of Baneh, Saghez and Sanandaj.
The referendum took place in the three provinces that officially make up the Kurdish autonomous region -- Dahuk, Irbil, and Sulaymaniyah -- and some neighboring areas. These areas include disputed cities such as oil-rich Kirkuk, Makhmour, Khanaqin, and Sinjar, over which Kurdish Peshmerga fighters have established control while fighting against Islamic State (IS) militants who captured large parts of northern Iraq and neighboring Syria in 2014.
The UN -- as well as the United States and other Western powers -- expressed concern that the referendum would pull attention away from the efforts to defeat IS.
U.S. State Department spokeswoman Heather Nauert criticized the referendum.
"The United States' historic relationship with the people of the Iraqi Kurdistan region will not change in light of today's nonbinding referendum, but we believe this step will increase instability and hardships for the Kurdistan region and its people," she said.
In New York, UN Secretary-General Antonio Guterres also said he was concerned about the "potentially destabilizing effects" of the referendum.
While saying he supported "the sovereignty, territorial integrity, and unity of Iraq," Guterres called for "structured dialogue and constructive compromise" between Baghdad and Kurdish leaders to resolve their differences.
With reporting by Reuters, AP, AFP, and dpa