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.