KYIV, Ukraine — As Ukrainian officials celebrate the arrival of more advanced Western air-defense systems and claim growing success at shooting down Russian rockets and drones, they are warning that Moscow is buying new long-range weapons against which Kyiv’s forces have little defense — specifically, ballistic missiles from Iran.
With movement on the ground slowing, the battle in the skies above Ukraine is increasingly central to the course of the war, and both sides are looking to their allies for new weapons. In the past month, Moscow’s forces have dramatically stepped up strikes far behind the front lines on cities and vital services like power, heat and water. These are part of a lethal campaign to tear down Ukrainian daily life and morale.
Ukrainian and Western officials say Russia’s stocks of precision-guided missiles and drones have run low, prompting it to turn to Iran. A spokesman for the Ukrainian Air Force said on Monday that Moscow and Tehran had finalized an agreement to deliver Iranian Fateh-110 and Zolfaghar ballistic missiles to Russia, which several news organizations confirmed, citing unnamed sources.
A Pentagon spokesman, Brig. Gen. Pat Ryder, said on Tuesday, “I can’t corroborate that information,” but he called the reports worrying. He added, “When we see Iranian ballistic missiles being employed on the battlefield in Ukraine, we will do what we can to illuminate that.”
Ukrainian air defenses have been highly successful at shooting down drones and cruise missiles, though some get through and cause enormous damage, but ballistic missiles, which fly much faster, are a tougher challenge. This week, the United States and its allies delivered to Ukraine its first two NASAMS air defense missile launchers, with more on the way, adding to Kyiv’s growing arsenal of Western and Soviet-legacy air defense systems. But the new additions are not designed to be effective against ballistic missiles.
“As of today, we can say that the recent escalation of Russian missile and drone terror has only resulted in the world responding — responding with new aid to Ukraine,” President Volodymyr Zelensky said in his overnight address on Monday.
He and his aides signaled that their position on peace with Russia, far from softening, was harder than ever, after reports that behind the scenes, the Biden administration had urged Kyiv to be open to negotiation.
Mr. Zelensky laid out in stark terms his conditions for any talks with Russia, terms that would be seen by President Vladimir V. Putin of Russia as a humiliating defeat: restoration of Ukraine’s “territorial integrity,” meaning the return of Russian-occupied lands, compensation for the damage caused by Russia’s war and prosecutions for war crimes. World leaders, he said, should “force Russia into genuine peace negotiations.”
Ukraine had “repeatedly proposed” a resumption of peace talks, Mr. Zelensky said, only to have Russia respond “with new terrorist attacks, shelling or blackmail.” No such talks have occurred in several months.
Oleksiy Danilov, the head of the Ukrainian national security council, added another condition on Tuesday: modern weaponry for Ukraine to defend itself.
One of Mr. Zelensky’s top advisers, Mykhailo Podolyak, tweeted that while “Ukraine has never refused to negotiate,” talks could not begin until Russian troops withdrew from Ukraine. He added that since Mr. Putin did not appear ready to do so, “we will talk with the next leader” of Russia.
The United States government has insisted publicly that how long and hard Ukraine will fight is up to its leaders, not Washington’s, a point General Ryder reiterated. “Ukraine will decide when they’re ready to negotiate,” he said.
The British news outlet Sky News reported on Tuesday that in addition to buying Iranian munitions, Russia had sent Iran sophisticated Western antitank and antiaircraft missiles that were captured in Ukraine, presumably for the Iranians to copy. General Ryder said he knew of the report but could not confirm or deny it.
Some models of Iranian missiles have ranges of several hundred miles. Fired from Russian-controlled territory, Iran’s missiles could strike anywhere in Ukraine.
Iran has indicated that it planned to sell ballistic missiles to Russia. It has also denied selling attack drones, though the wreckage of them has now been found many times in Ukraine, and social media accounts associated with the Iranian security services have boasted of their use there.
Maj. Gen. Kyrylo Budanov, head of Ukraine’s defense intelligence directorate, has said delivery of Iranian missiles could happen by the end of November.
“It’s a serious threat because Iranian missiles, unlike Russian ones, are quite high-precision, very high-speed, and those features have been battle-proven,” he said in a recent interview with the War Zone, an online publication focused on military matters.
In the weeks after Russia invaded in February, Ukraine’s critical need was portable antitank missiles to stop the advance. After the Russian offensive slowed into a grinding strategy of shelling cities and towns before trying to take them, the Ukrainians needed more and better artillery. Now it is air defenses.
Ukraine has been asking Western countries for systems that can shoot down ballistic missiles, which travel at several times the speed of sound, making them much harder to hit in flight than cruise missiles or slow-moving drones. General Budanov referred to the possibility of weapons that could strike missile launch sites, but the United States and others have been reluctant to give Ukraine the means to hit targets inside Russia, which the Kremlin has warned would be a dangerous escalation.
Ultramodern German IRIS-T air-defense systems — so new that they had never before been used on the battlefield — were extremely effective in shooting down missiles fired by Russia during a wave of strikes at the end of October, according to the Ukrainian military. But that system and the NASAMS are not designed to defend against ballistic missiles, and are expensive to use against relatively cheap drones.
Ukrainian officials estimate that Russia has used up about 80 percent of its prewar supply of precision weapons like Iskander ballistic missiles and Kalibr cruise missiles.
Marc Santora and Andrew E. Kramer reported from Kyiv, Ukraine, and Shashank Bengali from London. Richard Pérez-Peña and Farnaz Fassihi contributed reporting from New York, and Eric Schmitt from Washington.