Airplanes are parked on the tarmac of Moscow's Sheremetyevo airport in June 2013. Ukraine said it will close its airports next month to Russia’s largest airlines, including the regional leader, Aeroflot. (Sergei Karpukhin/Reuters)

The Ukrainian government said Friday that it will close its airports next month to Russia’s largest airlines, including the regional leader, Aeroflot, according to a published statement and government officials.

If the closure is enforced, it would create considerable headaches for travelers in the region and add new fuel to a military and political conflict between Moscow and Kiev that has been raging for more than a year.

The Russian government threatened to retaliate Friday by banning Ukrainian airlines, a decision that Russia’s transport minister said could “lead to the factual halt of air travel between the two countries.”

Russia annexed the Ukrainian peninsula of Crimea last year, and Moscow has been accused of providing men and materiel to separatists fighting the government in Ukraine’s southeast. The conflict has spilled over into the economy, affecting cross-border travel and trade.

This month, Ukrainian President Petro Poroshenko signed into law sanctions against 388 individuals and 105 companies, including several dozen airlines.

“Airlines with the Russian tricolor have no reason to be in Ukrainian airports,” Prime Minister Arseniy Yatsenyuk told the Ukrainian cabinet Friday, according to a statement posted on a government Web site.

Kiev also banned Russian planes bearing soldiers or military cargo from flying through Ukraine’s airspace and blocked government agencies from using software produced by Kaspersky Lab, the Russian maker of antivirus software.

A spokesman for Ukraine’s Infrastructure Ministry confirmed that the ban would begin Oct. 25, the “beginning of the winter navigation period,” and that all Russian airlines would be notified Friday about the closure.

A spokeswoman for Sheremetyevo airport in Moscow said she was aware of the order but noted that no directives to cancel flights had been made.

In an e-mailed statement Friday morning, Aeroflot said it had “not received official notification about halting flights from the Ukrainian aviation authorities.”

“According to international aviation laws, only the aviation authorities of the government may cancel flights into the country,” the statement continued. “As soon as Aeroflot receives an official notification from Ukraine’s aviation authorities to cancel flights, the company will inform its passengers about this.”

Aeroflot and Transaero, another Russian national airline banned by name in the Ukrainian statement, fly more than a half-dozen flights from Moscow to Kiev every day.

Fighting has died down in southeast Ukraine in recent weeks, but progress on the Minsk accords, as the political settlement process is called, has come to a standstill.

Poroshenko and Russian President Vladimir Putin will meet Oct. 2 with the leaders of France and Germany in Paris for further talks on a political settlement.

Also Friday, separatist leaders in a region of southeast Ukraine said they would eject the United Nations refugee agency and the humanitarian group Doctors Without Borders amid deep suspicion of Western aid agencies.

Doctors Without Borders is being forced to leave because separatist leaders said the organization may be trafficking illegal drugs into the regions. The group called the accusations false and said the separatists had “tried to intimidate our team by bringing armed men into the office.”