North Korea's military is growing stronger even as its economy teeters on the brink of collapse, an independent think-tank said on Wednesday, calling for better measures to repel the threat from a country that has twice tested a nuclear bomb.

Just over two weeks after the reclusive state's leader Kim Jong-il died, North Korea has made it clear its top priority is maintaining a songun, or military-first, policy whereby the army takes precedence over everything else.

The Seoul-based Korea Economic Research Institute said in a report that in 2011 North Korea operated a 1.02-million-strong army and a record number of tanks, warships and air defence artillery.

The depressing reality is it would not be entirely wrong to say North Korea's military strength is stronger than the South's based on the most updated data from 2011, the institute said.

The only way to deter a pre-emptive attack by the North is to make it clear that the South Korean forces will assume it is a precursor to a full-out war and strike back regardless of the nature of the aggression, even if it is a small-scale regional guerrilla war.

While the North has fewer combat aircraft than in 1986, its air power has been boosted by top-class MiG-29 fighter jets since the 1990s, the institute said. It also said there have notable increase in the number of submarines.

But analysts say most of the North's land combat vehicles are aged, and that its low fuel supplies mean it would be unable to sustain any long military operation.

South Korea's armed forces number nearly 700,000, and even with the backing of 28,000 U.S. troops, they are far outnumbered by the North.

Most of the impoverished North's finances are used to develop its programmes to build weapons of mass destruction.

The North has come under international sanctions since 2006 for testing nuclear devices and long-range missiles. In late 2010, it unveiled a uranium enrichment facility, which has opened a second route to make an atomic bomb along with its plutonium programme.


Analysts say that the young and inexperienced new leader, Kim Jong-un, who is heading a third generation of dynastic rule in the North, will stick to his father's militaristic approach.

They say he could take action, such as a military attack or more nuclear or missile tests, to burnish his credentials as an iron-fisted leader in the same mould as his father and grandfather.

The North has threatened to turn the South's capital, Seoul, into a sea of fire on numerous occasions and repeated that rhetoric again last week.

North Korea has a long history of using bellicose language against the South, especially since the conservative government of Lee Myung-bak took office in 2008 and ended a policy of engagement with the North.

The South's Defence Ministry said on Wednesday it would sign a joint operational plan with Washington this month to counter potential aggression, and increase the number of joint exercises with U.S. forces.

The ministry said this move was part of efforts to stay alert and guard against North Korean threats.

The threat of provocation by North Korea remains a constant possibility as Kim Jong-un moves ahead with building his regime, it said in a report to the president.

Our military will annihilate the enemy's will to mount repeat aggression by striking back sufficiently against the source of the threat and any supporting element until the enemy threat is completely removed.

The North has in the past lashed out against joint U.S-South Korean drills, saying they themselves are a provocation and are a tantamount to practice for an invasion.

Seoul has revamped its defences since 50 South Korean soldiers were killed in two separate attacks in 2010.

It has boosted artillery defences on west coast islands where the attacks took place, and changed its combat rules permitting tougher retaliatory responses.

South Korea increased military spending by 5 percent to 33 trillion won in the 2012 budget.

(Additional reporting by Jack Kim and Iktae Park; Editing by Robert Birsel)