KYIV, Ukraine — Flame and dense smoke billowed over a Russian airfield on Tuesday after what appeared to be a third drone strike in two days by Ukraine at a military base on Russian soil, signaling a bolder phase of Ukrainian attacks enabled by longer-range weapons and unconstrained by fear of reprisal.
After nine months of Russian bombardment of their towns and cities, Ukrainians cheered the taste of payback and the demonstration that their side could now reach deep into Russia, theoretically capable of hitting Moscow if it chose. The assaults also showed millions of Russians for the first time that they, too, might be vulnerable.
Ukraine’s new long-range striking ability came into focus on Monday with attacks on air bases some 300 miles from the nearest Ukrainian territory, demonstrating the ability to evade Russian air defenses and hit with precision. Both the Russian government and a senior Ukrainian official, who spoke on the condition of anonymity to convey sensitive information, said they were carried out by Ukraine using drones.
“If Russia assesses the incidents were deliberate attacks, it will probably consider them as some of the most strategically significant failures of force protection since its invasion of Ukraine,” Britain’s defense ministry said in an intelligence assessment released on Tuesday.
On Tuesday, an explosion ignited fuel tanks near an air base in the Kursk region of southwestern Russia, about 80 miles from Ukraine. Russian officials said it was another drone attack but did not explicitly blame Ukraine.
The subject remains sensitive enough for Ukraine’s government to assiduously avoid any public acknowledgment of responsibility for the strikes. But there is a widespread sense among officials and civilians that, short of nuclear escalation, there is little more Russia can do to Ukraine in retaliation that it is not already doing, with its waves of strikes on the country’s energy grid and other infrastructure.
“If somebody attacks you, you fight back,” Andriy Zagorodnyuk, a former Ukrainian minister of defense, said in an interview, clarifying that he did not speak for the government and could not confirm the strikes. “You cannot consider, this person will attack you because you are fighting back. There is absolutely no strategic reason not to try to do this.”
As of this week, he added, “the understandings of Russians that they are invincible and cannot be reached in Russia is not going to be there.”
Western analysts agreed that there was little risk of escalation by Moscow. Russia has already escalated, said Robin Niblett, former director of Chatham House, the London research institution, “by destroying Ukrainian infrastructure to try to change the strategic context of the war, force Ukraine to the negotiating table and warn Europeans that it becomes more expensive day by day to rebuild Ukraine.”
Kyiv has sought since early in the war to take the fighting to Russia. Within a month of the invasion in February, the Ukrainian military staged a helicopter assault on fuel depots in Russia, prompting the first Russian air raid alarm since World War II. Explosions at ammunition warehouses, railroad bridges, fuel depots and military bases inside Russia and Russian-occupied regions of Ukraine followed.
But those attacks were launched at fairly close range, no more than a few dozen miles.
In October, the Ukrainian state weapons manufacturer, Ukroboronprom, said it was finalizing development of a drone with a range of more than 600 miles and a 165-pound warhead. And on Sunday — a day before two distant Russian bases were hit — the company said it had completed testing of the new weapon.
Russia’s Ministry of Defense said the strikes on Monday used Soviet-era, jet-powered drones. Arms experts said the particular aircraft was probably the Tupolev TU-141 Strizh, a surveillance drone first developed by the Soviet Union in the 1970s and repurposed by the Ukrainians, possibly carrying an explosive. Analysts say it can fly at 600 miles per hour at low altitudes, much like some cruise missiles, making it difficult to detect and shoot down.
The attacks are “a kind of symbolic gesture,” said Douglas Barrie, a military aerospace expert at the International Institute for Strategic Studies in London. “You go after the bomber bases with something you’ve got in your inventory, or in the museum, or you’ve got hidden at the back of your airfield because you haven’t used it for a long time.”
Though the attacks this week do not appear to have diminished Russia’s military capacity significantly, Ukraine’s determination to strike inside Russia could pose a challenge for the Western allies, which are determined not to be drawn into a shooting war with Russia.
“We have neither encouraged nor enabled the Ukrainians to strike inside of Russia,” Secretary of State Antony J. Blinken said at a news conference on Tuesday. “But the important thing is to understand what Ukrainians are living through every day, with the ongoing Russian aggression against their country, and our determination to make sure that they have in their hands, along with many other partners around the world, the equipment they need to defend themselves and to defend their territory.”
The United States and other NATO countries have consistently declined to provide Kyiv with Western weapons that could reach targets far into Moscow’s territory, like the ATACMS missile, which has a range of up to 190 miles, with much higher speed and more explosive power than a drone. The allies have also been unwilling to provide Ukraine with the modern Western tanks and fighter jets it has requested.
But Ulrich Speck, a German foreign policy analyst, said that Russian threats to ratchet up the war, particularly with nuclear weapons, have rung increasingly hollow. World leaders friendly to President Vladimir V. Putin of Russia, including President Xi Jinping of China and Prime Minister Narendra Modi of India, have warned against it, and U.S. officials have threatened unspecified dire consequences if the Kremlin takes that step.
NATO and Washington, Mr. Speck said, “have accepted that the Ukrainians are driving this forward, and over time, fear of Russian escalation has receded.”
Russian airfields and the warplanes based there have been used to launch many of the missiles that Moscow’s forces have used for months to pummel Ukraine far behind the front lines, killing civilians and damaging vital services like housing, power, heat and water.
Mick Ryan, a retired Australian Army officer, wrote on the Substack blogging platform of Ukraine’s new readiness to attack inside Russia: “It is not, as some are sure to claim, an escalation. But it is a necessary political and military measure for Ukraine to limit the humanitarian harm of Russia’s brutal drone and missile attacks.”
The Engels air base on the Volga River, one of those hit on Monday, is the kind of sensitive target the United States and its allies have feared Ukraine might hit with long-range Western weapons, if it had them. The base is home to a number of Russia’s long-range, nuclear-capable bombers, a component of Russia’s nuclear deterrent force, and there have been unconfirmed reports that some of those bombers were damaged in the attack.
Ukrainian officials do not believe Russia has capacity to escalate its conventional military assault on their country in response, and in fact hope that attacks on Russian soil will degrade that ability, said Mr. Zagorodonyuk, the former defense minister.
“The consideration, from what I can see, is that Russia will use any available means, regardless of our responses, in order to coerce Ukraine into submission,” he said. “That is their strategic plan.”
Reporting was contributed by Lara Jakes in Rome, Steven Erlanger in Brussels, Marc Santora in Kyiv, Ukraine, Richard Pérez-Peña in New York and Michael Crowley in Washington.