The U.S. embassy in Iraq issued a statement warning citizens of possible unrest ahead of the Kurdish region's controversial vote on independence that's scheduled for Monday.
“In particular, U.S. citizens should avoid travel into and within territories disputed between the Kurdish Regional Government (KRG) and the Government of Iraq,” the travel warning noted.
Baghdad, the United States and the United Nations have all voiced strong opposition to the vote, warning it could further destabilize the region.
"The costs of proceeding with the referendum are high for all Iraqis, including Kurds," Heather Nauert, a spokesperson for the U.S. Embassy Baghdad, said in a statement.
The referendum is set to be held in the three provinces that make up the Kurdistan region as well as multiple towns and villages that are claimed by the Kurds and the Iraqi central government.
"Already the referendum has negatively affected Defeat-ISIS coordination to dislodge ISIS from its remaining areas of control in Iraq," Nauret added. "The decision to hold the referendum in disputed areas is especially de-stabilizing, raising tensions which ISIS and other extremist groups are now seeking to exploit."
The Kurdish region's president Masoud Barzani vowed to go ahead with the vote despite pressure from Baghdad and the international community. He said the referendum will be the first step in a long process to negotiating independence.
"Only through independence can we secure a future where we will not have the past atrocities," Barzani said, referring to the killings that occurred at the hands of Saddam Hussein's army that left more than 50,000 Kurds dead.
Late Sunday night, Iraq's central government in Baghdad ordered the Kurds to hand over all border crossings and airports.
Iraqi Prime Minister Haider al-Abadi also re-emphasized his call for the vote to be canceled.
"The map of Iraq is suffering attempts at division and tearing up of a united Iraq. Discrimination between Iraqi citizens on the nationalist and ethnic foundation exposes Iraq to dangers known only by God," al-Abadi said.
Iran, which shares a border with Sulaymaniyah, Kurdistan, closed its airspace to flights taking off from the region ahead of the controversial vote.
The Associated Press contributed to this report.