President Putin told the visiting General-Secretary of the Communist party, Nguyen Phu Trong, that he wanted closer military and security ties with Hanoi.
The two, meeting in the Black Sea resort of Sochi, signed a series of cooperation agreements including over oil and gas development in the South China Sea.
Direct threats from China in recent years have deterred some European oil companies from involvement in the disputed waters.
Russia, the United States and Japan, however, have shown more determination to stand up to China and to continue exploration and extraction operations in waters that fall within Vietnam’s EEZ.
The deal in Sochi involves a greater role for the Russian oil giant, Gazprom.
Russia’s other big producer, Rosneft, began drilling off Vietnam’s southeast coast earlier this year despite rumblings from China, which claims the area falls within its much contested “nine-dash line”, a claim to historic ownership of much of the South China Sea.
Russia also remains a major arms supplier for Vietnam, helping to boost its naval fire power with the delivery of Kilo class submarines.
Vietnam has been working hard to encourage the economic and naval presence of world powers in the South China Sea to offset its own sense of isolation and vulnerability in the face of a major Chinese military buildup.
A British warship, HMS Albion, docked in Ho Chi Minh City this week after passing through the Chinese controlled Paracel chain, which is also claimed by Vietnam.
China sent ships and helicopters to try to warn off the British
vessel, which was conducting a “freedom of navigation” in response to appeals from the US.
The aim was to challenge what are seen as “excessive” claims to territorial waters around Chinese bases and outposts – although the ship did not pass within the 12 nautical mile baseline claimed by China but not recognised internationally.
Britain is far from being a significant power in the region – however, Vietnam is keen to see the engagement of as many players as possible, with special focus on the US, Japan, India and Russia.