(Reuters) – The forces responsible for Russia’s strategic nuclear arsenal will conduct major exercises this month involving more than 4,000 soldiers, the Defence Ministry said on Wednesday, in the latest sign of rising tension with NATO over the Ukraine crisis.

In an announcement a day before the start of a NATO summit in Wales, RIA news agency quoted the ministry as saying the exercises would take place in Altai in south-central Russia and would also include around 400 technical units and extensive use of air power.