Seoul: South Korea's president opened the door on Monday to possible nuclear talks with North Korea and warned the neighboring country to avoid any provocations, saying the Korean peninsula is at a crucial turning point.

Lee Myung-bak's comments in a nationally televised speech come as the young son of the late Kim Jong Il takes power in North Korea as Supreme Commander of the military and ruling party leader after Kim's death last month.

The North vowed on Sunday in a New Year's message that it would bolster its military and defend the son, Kim Jong Un, "unto death."

"The situation on the Korean peninsula is now entering a new turning point," Lee said. "But there should be a new opportunity amid changes and uncertainty."

Lee warned that South Korea would sternly respond to any North Korean provocation. In 2010, 50 South Koreans died in attacks blamed on the North, though the Koreas have met in recent months for preliminary nuclear discussions.

North Korea, which has tested two atomic devices since 2006, has said it wants to return to long-stalled six-nation talks on halting its nuclear weapons program in return for aid.

Washington and Seoul, however, have insisted that the North first show progress on past disarmament commitments.

If North Korea halts its continuing nuclear activities, Lee said in his speech, negotiations could resume.

"We are ready to resolve security concerns on the Korean peninsula and provide assistance to revive North Korea's economy through agreements in the six-nation talks," Lee said.

North Korea, however, has so far taken a hard line toward the South. It warned last week that there would be no softening of its position toward South Korea's government after Kim Jong Il's death.

North Korea's powerful National Defense Commission said the country would never deal with Lee.

(Agencies)