LONDON (Reuters) - British defence minister Ben Wallace said on Monday that he does not expect Russian President Vladimir Putin to use nuclear weapons in his pursuit of Ukraine, days after the former Soviet republic invaded its neighbour.

       "We should be worried that a state like Russia believes that the rules don't apply to them, whether that is invading Ukraine or using nerve agent in Salisbury, but fundamentally a deterrent is what it is, a deterrent," Wallace told Times Radio.

       "As much as he might be ambitious for Ukraine, I don't think he wants to go into that space."

       (Reporting by William Schomberg and Muvija M, Editing by Alistair Smout)