Like other US and western officials recently, Sir Jeremy Fleming did not suggest there had been any signs of suspicious activity."Any talk of nuclear weapons is very dangerous and we need to be very careful of how we are talking about that.But he warned that the missile attacks on targets across Ukraine on Monday showed Russia was still "very capable" of causing damage.The director of the intelligence, cyber and security agency said the costs to Russia of the war in Ukraine - in terms of both people and equipment - were "staggering" as early gains were being reversed.During Tuesday's speech, he also warned that China was seeking to create "client economies and governments" by exporting technology to countries around the world, and said these countries risked "mortgaging the future" by buying in Chinese technology with "hidden costs"."