Russia has launched so many missiles into Ukraine that “they’re having inventory issues with precision guided munitions and they’re having trouble replacing” them, the senior Pentagon official, who requested anonymity, told reporters.

The official told a press briefing that, based on US intelligence, Washington believes the sanctions — particularly on electronic components — have “had an effect on the Russian defence industrial base.”

This is why large cities such as Mariupol or Kharkiv are hit by unguided bombs that do not distinguish between a military target and a residential building, the official claimed.

Furthermore, Russian forces continue to suffer from supply and discipline problems, including among officers who are “refusing to obey orders and move”, the official continued.

Moscow for its part has not made clear how the sanctions have impacted Russia’s military inventory.

According to the Pentagon official, the Russian operation in the south of the country, faced with stubborn Ukrainian resistance, has made “virtually no progress”.

That includes the Donbas region where Russian forces are failing to coordinate their airstrikes and ground manoeuvres while contending with weather that makes the ground muddy and forces tanks to stay on paved roads, the official said.

The Russians are also still struggling with logistical issues, the official said, adding they are “struggling to resupply their troops”.