Iran has pointedly shown its opposition to Monday’s independence referendum in Iraqi Kurdistan, closing its airspace to all flights from the region.

A spokesman for the Supreme National Security Council said, “At the request of the central government of Iraq, all flights from Iran to Sulaymaniyah and Erbil airports as well as all flights through our country’s airspace originating in the Iraqi Kurdistan Region have been halted.”

Keyvan Khosravi said the measure came after Iran’s “political” efforts proved ineffective in halting the vote. He warned that “hasty decisions” officials of the Iraqi Kurdistan Regional Government would limit the capability of Iraqi Kurds for engaging in constructive dialogue within Iraq and would pose serious challenges to the security of the Kurdish people, Iraq, and the region.

On Sunday, President Hassan Rouhani spoke with Turkish counterpart Recep Tayyip Erdoğan about the opposition of both countries to the referendum.

Erdoğan’s office said in a statement, “The two leaders noted that not cancelling the referendum will bring with it chaos to the region and they also stressed the great importance which they attach to Iraq’s territorial integrity.”

“The two leaders noted that not cancelling the referendum will bring with it chaos to the region and they also stressed the great importance which they attach to Iraq’s territorial integrity,” the statement added.

Iran has made a series of statements through the summer objecting to any Iraqi Kurdish move towards independence. The Supreme Leader’s top aide, Ali Akbar Velayati, conveyed Ayatollah Khamenei’s line on September 16, saying the Iraqi Kurds would be serving the interests of the US and Israel: “The Islamic Republic of Iran opposes any move either knowingly or unknowingly towards independence of one part of Iraq or any other country in the region.”

The UN and US have also backed Iraq’s central government in its opposition to the vote.