Strikes deep inside Russia highlight Ukraine’s tactical ingenuity

Ukrainian officials have recently been hinting at developments in the country's grinding war with Russia. A long-range rocket, perhaps? Or a homemade modified drone? The apparent evidence of a new and unexpected weapon was visible on Monday morning, when mysterious explosions hit two Russian airbases.

Both took place a long way from the frontlines. Video from Russian social media showed a blast at the Engels-2 airbase in Russia's Saratov region. Another happened at the Dyagilevo military airbase near Ryazan, a city just 150 miles from Moscow and Vladimir Putin's Kremlin. According to Russian state media, three people at the base were killed and five injured when a fuel truck went up in flames. At least two planes were reportedly damaged.

The exact cause of the explosion was uncertain. But it appears Ukraine has found a way to target Russia's long range Tu-95 and Tu-22M aircraft, which are stationed at the airstrips. Since October the Kremlin had used these strategic bombers to wreck Ukraine's energy infrastructure, bit by bit, leaving millions without heat and electricity as winter arrives.

There is speculation Kyiv has developed a strike drone with an astonishing 1,000km range. Late last month a Ukrainian serviceman said the weapon had already been used against the Russian military. If accurate, this means much of European Russia is now in reach. And that the asymmetric advantage Moscow has enjoyed this year - the ability to launch cruise missiles safely from deep inside Russia itself - is under threat.

"We attack where they are weak and defend where they are strong," Andriy Zagorodnyuk, Ukraine's former defence minister said. He described Ukraine's military tactics as essentially "opportunistic". Russia by contrast, he continued, was waging an all-out "unidirectional" assault to capture the town of Bakhmut, in the eastern Donbas region, despite huge losses of Russian soldiers and equipment.

Most military observers expect the frontlines of the war to be largely static over the next few freezing months, following spectacular Ukrainian counter-attacks during the autumn, in which Kyiv recaptured almost all of Kharkiv oblast in the north-east and liberated the city of Kherson in the south, together with territory on the right bank of the Dnipro River. There could be further offensives before spring, Zagorodnyuk said.

The latest guerilla-style raid on Monday shows Ukraine's tactical ingenuity in its bitter battle against Russia. And Kyiv's continuing capacity to surprise. In late October Ukraine caught Moscow unawares when it launched an early morning air and sea drone attack on the Crimean port of Sevastopol, home to Russia's occupying Black Sea fleet. Several Russian frigates were reportedly disabled, including the Admiral Makarov flagship.

Naval analysts said they believed Ukraine had developed an ingenious and lethal sea drone. Its components included a modified jet-ski and a remotely controlled camera, with a live feed back to a command and control centre. Plus explosives, attached to the front. Drones also appeared to have played a role in another successful Ukrainian attack in August on the Saky airbase in Crimea, in which nine Russian warplanes were blown up.

Kyiv does not always tell its allies before it conducts certain types of risky military operations, western officials said. They believe the Ukrainians deliberately avoid disclosing attacks the west might try to dissuade them from carrying out, having previously come under pressure to abandon certain strikes. Attacks deep inside Russian territory are an area of particular sensitivity.

The Biden administration has indicated it is wary of coming into direct military conflict with Russia and fearful of nuclear escalation. The Kremlin says it is already at war with the US, and the west - and considers Ukraine to be a US-run puppet state. The White House has supplied Kyiv with almost $20bn in military and security assistance so far, but has refused to deliver long-range munitions that would allow Kyiv to strike Russia directly.

Instead Volodymyr Zelenskiy's government has used its own technology for special operations. They include an attack in October on the Russian bridge across the Kerch straight linking Russia with occupied Crimea. And in April the dramatic sinking of the Moskva battle cruiser, carried with two Ukrainian anti-ship Neptune missiles. Both were humiliating blows to Russia's prestige. Further surprises can be expected.