Seoul: South Korea prepared on Wednesday for a major live-fire drill involving fighter jets and tanks near the tense North Korean border, as Seoul and Washington reacted warily to overtures from Pyongyang.
South Korea`s military said Thursday`s ground and air firing exercise 20 kilometres (12 miles) south of the mainland border would also involve self-propelled guns and 800 soldiers.
Although similar drills have been held at the same firing range at Pocheon many times before, the latest exercise comes with Seoul on high alert for a possible attack from its wayward neighbour.
South Korea`s navy meanwhile began a four-day firing drill Wednesday off the east coast, a relatively distant 100 kilometres (60 miles) south of the border with the North, mobilising six warships plus helicopters.
The military said it would practise responses to intrusions by North Korean submarines and patrol boats.
And South Korean marines were posted to guard a Christmas tree that was lit up Tuesday near the land border, reflecting fears that the North might fire on the display as a propaganda symbol.
Tensions have been high since the North shelled an island near the contested western maritime border last month in response to a live-fire drill by the South. The bombardment of Yeonpyeong killed four people including civilians.
The South staged a repeat drill on Yeonpyeong Monday but the North did not go through with threats to hit back, saying it "did not feel any need to retaliate against every despicable military provocation".
A senior South Korean military commander said Thursday`s drill at the Pocheon range would "demonstrate our solid military preparedness".
"We will retaliate thoroughly if the North commits another provocative act like the shelling of Yeonpyeong," First Armoured Battalion commander Choo Eun-Sik told Yonhap news agency.
The North`s comments late Monday eased fears of war on the peninsula, and it also reportedly offered nuclear concessions to visiting US politician Bill Richardson.
But Seoul and Washington have expressed scepticism about the apparent overtures, coming after an intense bout of sabre-rattling from Pyongyang, whose hardline communist regime is undergoing a generational power shift.
The United States said that North Korea was not even "remotely ready" to resume six-nation nuclear disarmament talks, despite the apparent concessions offered to New Mexico Governor Richardson on his private trip.
The White House made clear there was no change to US policy, despite Pyongyang`s reported offer to re-admit UN nuclear inspectors and sell off fuel rods which could be used to produce plutonium.
President Barack Obama`s spokesman Robert Gibbs said Pyongyang had, over many years and different US administrations, failed to match its words with actions.
"We`re not going to get a table and a room and have six-party talks just for the feel-good notion of having six-party talks," he said.
"When and if the North Koreans are ever serious about living up to their obligations, then we can think about restarting six-party talks."
North Korea pulled out of the nuclear talks -- which involve the two Koreas, the United States, Russia, China, and Japan -- in April 2009 and ordered UN nuclear inspectors out of the country.
It staged a second nuclear test a month later.
Its disclosure last month of an advanced uranium enrichment plant -- purportedly to serve a peaceful nuclear power programme -- heightened regional security fears.
Richardson, a veteran troubleshooter with the North who was formerly a US ambassador to the UN, unveiled Pyongyang`s apparent concessions after a visit that the White House stressed was unofficial and independent.