Moscow has said it will be forced to strengthen its defences in the Baltic if Finland and Sweden join Nato, including by deploying nuclear weapons, as the war in Ukraine entered its seventh week and the country braced for a major attack in the east.

However, the Lithuanian defence minister, Arvydas Anušauskas, claimed on Thursday that Russia already had nuclear weapons stored in its Baltic exclave of Kaliningrad, which borders Lithuania and Poland. That claim has not been independently verified, but the Federation of American Scientists (FAS) reported in 2018 that nuclear weapon storage bunkers in Kaliningrad had been upgraded.