LONDON — Ukraine’s military incursion into Russia has triggered new anxieties among Moscow elites over the direction of a war approaching the end of its third year, CIA Director William J. Burns said Saturday during a rare public appearance with his British counterpart.

       Ukraine’s seizure of territory in Kursk “did raise questions on the part of Russian elites — where is this all headed?” Burns said at a conference in London, alluding to previously undisclosed intelligence on reactions in the Russian capital. He called the surprise operation by the Ukraine military a “significant tactical achievement” that exposed Russian vulnerabilities but does not yet appear poised to hasten the end of the war.