US Defense Secretary Robert Gates and his wife Becky are greeted upon their arrival in St. Petersburg March 21, 2011. [Photo/Agencies]

ST. PETERSBURG, Russia - Robert Gates has arrived in Russia for what is expected to be his final visit as US Defense Secretary, and he's hoping to ease Moscow's worries over a missile defense shield in Europe and expand a military relationship that has grown dramatically since his Cold War days at the helm of the CIA.

Gates, who is expected to retire this summer, says Russian cooperation in the Afghanistan war and its support of UN Security Council resolutions against Iran underscore cooperation that has dramatically evolved in recent years. Russia also abstained in the recent United Nations vote for military intervention in Libya, effectively allowing the allied assault to go forward.

The Pentagon chief will meet with Russian leaders and speak to a class of Naval Academy junior officers.