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Jo Yong-hak, Pool, Associated Press
South Korea President Lee Myung-bak and his wife Kim Yoon-ok sing the national anthem during the 92th anniversary ceremony of Independence Movement Day against Japan in Seoul, South Korea, Tuesday, March 1, 2011.

SEOUL, South Korea — South Korea's president called Tuesday for serious talks with North Korea, warning that the rivals must not repeat their "dark history" and urging Pyongyang to abandon its nuclear programs.

President Lee Myung-bak made the remarks in a nationally televised speech amid worries over rising animosity following Monday's launch of annual South Korea-U.S. military drills, which Pyongyang calls a rehearsal for invasion. The North's state media said Tuesday that the drills could cause a "nuclear catastrophe" on the Korean peninsula.

"The Korean nation cannot afford to lag behind the currents of the times, repeating the dark history of yesteryear," Lee said, referring to the Koreas' bloody 1950-53 war and the subsequent decades of violence and tension. "Now is the opportune time to open a new kind of future on the Korean peninsula."

Lee said South Korea could provide aid to the impoverished North and is ready to resume inter-Korean talks "anytime with an open mind." He said, however, that "the North should step forward for serious dialogue and cooperation and refrain from developing nuclear weapons and missiles."

Lee, who spoke at a ceremony marking Korea's 1919 independence uprising against Japan's colonial rule, also said North Korea must take responsibility for "armed provocations."

Ties between the Koreas were badly strained after North Korea shelled a front-line South Korean island in November, killing four people. The barrage came eight months after 46 sailors were killed when a South Korean warship was sunk, which a Seoul-led international investigation blamed on a North Korean torpedo attack. Pyongyang denies involvement.

Lee refrained from using harsh rhetoric against North Korea, a marked contrast from past speeches that vowed stern and immediate retaliation against any new attacks by the North.

Earlier Tuesday, however, Lee's defense chief inspected front-line troops and ordered them to immediately return fire without reporting to him if the North attacks.

After high tension following its November bombardment of the South Korean island, North Korea had been calling for dialogue with Seoul and expressed a desire to return to stalled international talks on its nuclear program. Military officers from the Koreas met last month but failed to make progress.

Anger in the North was rekindled this week, as South Korea and the United States pushed ahead with annual military exercises despite North Korea's threat to retaliate.

As Lee spoke, Pyongyang's state media called the drills a dangerous plot to invade the North and warned of a full-blown war on the Korean peninsula.

"Chances for dialogue and peace on the Korean peninsula have evaporated, and the danger of war is increasing," the North's main Rodong Sinmun newspaper said in a commentary carried by the official Korean Central News Agency. "If a war breaks out on the peninsula, only a nuclear catastrophe will be triggered."

Later Tuesday, the North's Foreign Ministry issued a statement accusing Washington of attempting to use the drills as a chance to increase tensions and bolster its regional military power. However, it said the North is still ready for dialogue.

"The United States must be responsible for all consequences that its military provocation will cause," said the statement carried by KCNA. "We are ready for both dialogue and confrontation."

The North has also threatened to enlarge its nuclear arsenal and turn Seoul into a "sea of flames" in response to the drills. The country's military separately warned it would fire at South Korean border towns if Seoul continues allowing activists to send propaganda leaflets to the North.

On Tuesday, South Korean Defense Minister Kim Kwan-jin ordered front-line officers to quickly respond to any North Korean attacks. "Don't ask whether to shoot back or not. Act first before reporting it," Kim said, according to the Defense Ministry.

Soldiers were ready to return artillery fire within only a few minutes after a North Korean attack, the chief of an artillery unit reported to Kim, the ministry said. It didn't identify the officer.

South Korean and U.S. officials have repeatedly said the drills are purely defensive.

About 12,800 U.S. troops and some 200,000 South Korean soldiers and reservists are to participate in the drills, which are to last until late April. The training, which involves computer war games and live-firing exercises, is aimed at defending South Korea against any attack.

North and South Korea are still technically at war because the Korean War ended with an armistice, not a peace treaty.