MOSCOW (Reuters) - Russia will create three new military divisions on its Western flank in 2016 and bring five new strategic nuclear missile regiments into service, Sergei Shoigu, the country's defense minister, was quoted as saying by news agencies on Tuesday.

Shoigu's announcement was consistent with a multi-billion dollar overhaul of Russia's military, which is currently carrying out air strikes in Syria after helping annexe Ukraine's Crimea region in 2014.

Shoigu did not explain the motivation for forming the new divisions, but said it would be one of the most important tasks for the defense ministry this year. He said every military district should also expect to undergo spot checks in 2016.

"Our main effort should go into strengthening the potential of our strategic nuclear forces and of fulfilling the space defense program," the RIA Novosti agency quoted Shoigu as telling a meeting.

"Five rocket regiments, equipped with modern rocket complexes, will enter active service in 2016."

It was also necessary to steadily improve the infrastructure supporting the nuclear forces, he said, singling out the facilities where the country's nuclear-armed submarines and long-range nuclear bombers were based.

(Reporting by Maria Kiselyova and Polina Devitt; Writing by Andrew Osborn; Editing by Christian Lowe)