IRBIL, Iraq — Iraq’s prime minister, angered by a vote on independence by his nation’s Kurdish minority, today gave the country’s Kurdish region until Sept. 29 to surrender control of its two international airports or face a shutdown of international flights.

Kurdish leaders in northern Iraq had antagonized Iraq, Turkey and Iran by holding the referendum Sept. 25. The results have not yet been announced, but the Kurdish Regional Government said today that the vote had gone overwhelmingly in favor of independence from Iraq.

A “yes” vote would not lead to immediate independence for the semiautonomous region, but it would direct the regional government to begin the process of creating an independent state, including negotiating a separation with Baghdad.

Iraqi officials have called the referendum unconstitutional and have refused to negotiate with the Kurdish leadership. The Iraqis fear losing a third of the country and a major source of oil should Kurdistan break away.

Prime Minister Haider al-Abadi said his government had decided to demand control of the airports because the referendum had “destabilized” the region. He said humanitarian and other “urgent” flights would be exempt from the ban.

Referring to the Kurdish leadership, he added, “Unfortunately, some have tried to weaken Iraq and be stronger than the state.”

“We are partners in this country, and the partnership means we work together and don’t carry out unilateral decisions that lead to division and conflict and weakness,” al-Abadi said.

There was no immediate response by leaders of the Kurdistan Regional Government. In an address in Irbil on Tuesday night, Massoud Barzani, the region’s president, referred indirectly to al-Abadi’s ultimatum.

“We ask the Baghdad government not to threaten the Kurds because of the referendum,” he said. He urged the Iraqi government to enter negotiations and to respect what he said was the will of the Kurdish people to seek a nation of their own.

He added that the referendum had been approved by a wide margin, though he did not provide figures. Kurdish authorities are expected to announce the vote results Wednesday.

Turkey and Iran fear that a move toward independence by the Iraqi Kurds will inflame separatist fervor among their countries’ Kurdish minorities. Videos on social media showed Kurds in at least two Iranian cities celebrating the Iraqi Kurds’ vote.

The United States also opposed the vote, worried that it could set off ethnic conflict, break up Iraq and undermine the U.S.-led coalition against the Islamic State group.

Both Turkey and Iran have threatened sanctions against the Kurdish region, including the closing of border crossings. Turkish and Iraqi troops are conducting military exercises on Iraq’s northern border near Kurdistan, and Iranian forces are carrying out similar maneuvers on Iraq’s eastern border.

The Kurdish regional government, which has its own parliament and military force, operates international airports in its capital, Irbil, and in the northern city of Sulaimaniyah. There is no domestic Kurdish airline in the autonomous region.

Iraq asked other countries last week to halt flights into the Kurdish region, but only Iran complied.

Al-Abadi is expected to meet Wednesday with the Iraqi Parliament, which has voted to request that Iraqi troops be sent to disputed areas that are controlled by the Kurds but claimed by Baghdad. That would include the multiethnic, oil-rich city of Kirkuk, which the Kurds seized in 2014.

As the Islamic State rose in northern Iraq in 2014, Kurdish fighters took advantage of the chaos, and in some cases of fleeing Iraqi troops, to expand the Kurdish territory by 40 percent.

Parliament has also requested that the government consider closing land crossings linking Iraqi Kurdistan and the rest of the country.

The move by al-Abadi was viewed in Kurdistan as the beginning of a campaign to pressure the region to back away from independence.

For the Kurds, an independent state has been a national aspiration for generations. When borders in the Middle East were redrawn after World War I, the Kurds were denied a homeland. About 30 million Kurds are spread across Iraq, Iran, Syria and Turkey.

For decades, Baathist-led governments in Baghdad tried to crush or evict the Kurds from their traditional lands and replace them with Arabs. But the Kurds were protected from Saddam Hussein’s troops by a U.S. no-fly zone starting in 1991, and have since built a thriving proto-state across northern Iraq.