MOSCOW, March 19 (Reuters) - Russia will step up protection for high-ranking military officials after a series of assassinations and attempted killings that it blames on Ukraine, the head of the FSB security service was quoted as saying on Thursday.

In the most recent attack, Lieutenant-General Vladimir Alexeyev, the deputy head of the GRU military intelligence service, was shot three times in his Moscow apartment building on February 6. Ukraine denied involvement.

State media quoted FSB chief Alexander Bortnikov as saying that Alexeyev was recovering, and security for such senior figures would “of course” be tightened.

(Reporting by Reuters; Writing by Maxim Rodionov; Editing by Mark Trevelyan and Alex Richardson)