South Korea launched a major live-fire drill Thursday near the tense land border with North Korea in a show of strength marking the first anniversary of the sinking of one of its warships.

Tanks, armoured personnel carriers, artillery, helicopters and jets took part in the drill at the Pocheon range, 30 kilometres (19 miles) south of the border, the defence ministry said.

The show of force came a day after the North's military threatened to open fire if a planned launch of leaflets by anti-Pyongyang activists near the disputed Yellow Sea border goes ahead.

South Korea is also holding a week-long naval exercise that began on Monday to mark the first anniversary of its warship sinking on March 26 last year.

The South accused the North of torpedoing the ship with the loss of 46 lives. Pyongyang denies the charge.

The sea exercise reportedly includes three days of training by South Korean warships and aircraft from Friday, simulating attacks by North Korean submarines, ships and jet fighters.

Massive naval firing training will be held on Saturday at three locations off the peninsula.

General Han Min-Koo, chairman of the Joint Chiefs of Staff, called for strong and swift punishment of any military provocations by North Korea in the Yellow Sea.

"Our military must strongly punish the enemy with immediate and swift measures in case of contingencies" near the Yellow Sea border, he said after inspecting a drill by jet fighters in the southern city of Daegu.

The South, which has remained technically at war with its nuclear-armed neighbour since their conflict 60 years ago, says its drills are defensive.

But tensions between the two nations have risen since the North shelled a border island on November 23, killing four people.

This year South Korea has been staging a series of drills alone or together with US troops to test its battle readiness.

US and South Korean troops completed computerised joint war games on March 10, but joint field training will continue throughout March and April.

The North's military warned Wednesday that it would open fire if defectors from the communist country launch propaganda leaflets from Baengnyeong island, the closest land to the disputed sea border.

The defectors plan to launch leaflets on Friday or Saturday containing news of Arab uprisings and calling for the overthrow of the North's regime.

But residents in Baengnyeong island vowed on Thursday to block the leaflet launch for fear of a backlash from the North.

earlier related report
S.Korean island opposes anti-North leaflet launch
Seoul (AFP) March 24, 2011 - A South Korean island locked in a propaganda row aims to stop anti-Pyongyang activists from launching leaflets across the border for fear of a backlash from the North, a village leader said Thursday.

The decision, reached at a meeting of the heads of 18 districts in Baengnyeong island, came after the communist North issued a fresh warning that it would open fire at places where such leaflets are launched.

"We've decided to prevent the leaflet launch as it would make our hard life harder," Park Jun-Cheol, one of the district chiefs, told AFP by phone.

Pier workers, all Baengnyeong residents, would refuse to unload the shipment from a cargo ship early Friday, including 200,000 leaflets, large plastic balloons and helium gas tanks needed to launch the propaganda, he said.

"We will also block the piers with cars so that the ship cannot unload the truck carrying the leaflets and equipment," Park said.

Tourists have stopped visiting the island after the North shelled another frontline island in November last year in protest at Seoul's naval training near the disputed sea border in the Yellow Sea.

"During the high season, we used to receive some 1,000 tourists every day and tourists' dollars were a great source of our income. But inns and sushi bars are now all teetering on the verge of bankruptcy," Park said.

However, the activists vowed to go ahead with a plan to launch on Friday or Saturday helium-filled balloons that would carry leaflets containing news of Arab uprisings and calling for the overthrow of the North's regime.

"We must not be cowed into submission by North Korea's threats," a leading activist said.

The North's western frontline army unit said Wednesday its military "keeps itself fully ready to make sighting firing and blow up those bases for... madcap psychological warfare and go into action any time."

The leaflet launch was aimed to mark the first anniversary of the sinking of a South Korean warship off Baengnyeong island.

The South accuses the North of torpedoing the ship with the loss of 46 lives, a charge angrily denied by Pyongyang.

In November last year, the North shelled Yeonpyeong island in the Yellow Sea, killing four including two civilians, bringing the peninsula to the brink of war.

Pyongyang has threatened to open fire with artillery in retaliation for any pamphlet distribution near the border as the South's military has also reportedly sent leaflets with news of the Middle East revolts.