A statement by the Ministry of Defense confirmed that Graube had submitted his resignation to President Raimonds Vejonis but did not specify the reasons for the shock move.
Defense Minister Raimonds Bergmanis commended Graube for his work, saying:
"Lieutenant General Graube's experience, knowledge and commitment to the growth and development of the National Armed Forces has been significant and persistent. From the Minister of Defence point of view, I would have wished that Lieutenant General Graube would carry out his duties until the end of his term, but I respect the National Armed Forces Commander's decision."
Bergamanis said he was grateful for Graube's contribution and hoped that his expertise could still be called upon in future. "
General R.Graube has been at the helm of the armed forces for two terms from 1999 to 2003 and from 2010 to 2014, after which he was reappointed for a third four-year term, which has now been cut short.
His service in the National Armed Forces started in 1991.
Graube is well liked among service personnel for his down-to-earth manner. He has also proven to be a good communicator while increasing regional tensions have put the job of defense chief very much in the spotlight.
According to the National Armed Forces Law, Article 14, the National Armed Forces Commander is confirmed in office for four years and dismissed by the Saeima, upon the President's proposal.
Speaking to LTV's Panorama evening news show via telephone, Graube explained his resignation saying it was in effect simply a chance for someone new within te "military pyramid" to take over.
He had given the matter a lot of thought, he said, and reflected that he was the longest-serving NATO chief of defense, and that to be in the position so long was highly unusual.
"I also had the feeling I've completed my work," Graube said, citing the commitment already won to increased military spending and upgrades to Latvia's military equipment and facilities.
Consequently now would be "a good time to hand over to a new commander," Graube said, adding that he would remain in pace for another three months while a replacement is sought.
He also denied he has any immediate political ambitions.