North Korea must approach dialogue with South Korea with no strings attached if it genuinely wants to improve ties, a Seoul spokesman said Friday, after the communist state's leader mooted bilateral talks.

Pyongyang's leader Kim Jong-Un in his New Year speech said he was open to a summit with South Korea, but urged the United States and South Korea to stop their annual military exercises which he condemned as a "rehearsal of a nuclear war".

North Korean leader Kim Jong-Un proposed the "highest-level" talks with South Korea Thursday, opening the way to a historic summit as his communist country battles to fend off U.N. prosecution over its human rights record.

The sudden move, made during Kim's traditional New Year message, would clear the path for the first inter-Korean leaders' meeting since a 2007 summit in Pyongyang.

Even after Washington pointed the finger at North Korea for the massive cyberattack on Sony Pictures, some experts say the evidence is far from clear cut.

President Barack Obama earlier this month took the unusual step of naming North Korea for the crippling attack, while promising that the United States would "respond proportionately" after the FBI said evidence pointed to Pyongyang.

Every year, hundreds of North Koreans risk their lives escaping the reclusive nation, but the profile of those braving the dangerous border crossing has changed markedly from the famine-driven refugees of the past.

Where escape was once a desperate bid for survival by people on the brink of starvation, it is now often the calculated path taken by relatively affluent North Koreans who also know far more about an outside world that was a total mystery to earlier escapees.

U.N. chief Ban Ki-moon on Monday welcomed a South Korean proposal to hold high-level talks with North Korea and urged Pyongyang to accept the offer.

Ban, a former South Korean foreign minister, said dialogue was the only way forward to build trust and promote relations on the peninsula, which has been divided since 1945.

A top South Korean official offered Monday to hold high-level talks with North Korea in January, as Pyongyang battles growing pressure over human rights and a fresh cyber row with the U.S.

Ryoo Kihl-Jae, the South's unification minister in charge of North Korean affairs, said he was willing to meet in Seoul or the North's capital Pyongyang for the rare high-level talks. 

North Korea on Saturday blasted U.S. President Barack Obama as a "monkey" for inciting cinemas to screen a comedy featuring a fictional plot to kill its leader, and threatened "inescapable deadly blows" over the movie.

The isolated dictatorship's powerful National Defense Commission (NDC) also accused the U.S. of "disturbing the Internet operation" of North Korean media outlets.

The United States, Japan and South Korea have agreed a rare trilateral military arrangement on intelligence sharing about North Korea's nuclear and missile programs, officials said Friday.

The deal, which is to be signed on Monday according to South Korea's defense ministry, comes at a time of heightened concern about North Korea's nuclear and missile programs, which are seen as a major security concern in the Pacific region and beyond.

North Korea on Friday sent home a South Korean man who had crossed illegally into the impoverished communist state in an apparent attempt to defect.

Ma Sang-Ho, 52, was repatriated through the border village of Panmunjom and held by the South's security authorities for questioning, Seoul's unification ministry said.

Raunchy comedy "The Interview" -- a movie about a fictional plot to kill North Korean dictator Kim Jong-Un which has enraged Pyongyang -- opened in U.S. theaters Thursday, a move its star attributed to public pressure.