Vietnam will have a submarine fleet within six years, the defence minister reportedly confirmed on Thursday, in what analysts say is intended as a deterrent to China's increasing assertiveness at sea.
Russian media reported in December 2009 that Vietnam had agreed to buy half a dozen diesel-electric submarines for about $2 billion.
"In the coming five to six years, we will have a submarine brigade with six Kilo 636-Class subs," Defence Minister Phung Quang Thanh was quoted as saying by the state-controlled Tuoi Tre newspaper.
Thanh said the fleet was "definitely not meant as a menace to regional nations," according to the report.
"Buying submarines, missiles, fighter jets and other equipment is for self-defence," he was quoted as saying.
Ian Storey, a regional security analyst at the Institute of Southeast Asian Studies (ISEAS) in Singapore, said the submarine deal has been driven by events in the South China Sea, where China and Vietnam have a longstanding territorial spat over the Paracel and Spratly archipelagos.
Tensions rose after Vietnam in May accused Chinese marine surveillance vessels of cutting the exploration cables of an oil survey ship inside the country's exclusive economic zone.
"These purchases are designed to deter the Chinese from encroaching on Vietnamese sovereignty," Storey told AFP.
He said the country already operates two midget submarines bought years ago from North Korea.
In the newspaper report, Thanh did not specify how Vietnam was paying for its naval upgrade.
"It depends on our economic ability. Vietnam has yet to produce modern weapons and military equipment, which are costly to import," he said.
Analysts say the country's economy is in turmoil with galloping inflation, large trade and budget deficits, inefficient state spending, and other woes.
Much of Vietnam's military hardware is antiquated but this week it received the first of three new coastal patrol planes for the marine police, announced the manufacturer, Madrid-based Airbus Military.
Russian media reported last year that Vietnam ordered 12 Sukhoi Su-30MK2 warplanes in a deal worth about $1 billion.
Other nations in the region have accused China in recent months of becoming more aggressive in enforcing its claims to parts of the South China Sea.
The Philippines, Malaysia, Brunei and Taiwan also have overlapping claims to all or parts of the waters, which are potentially rich in oil and gas deposits and straddle vital commercial shipping lanes