South Korean President Moon Jae-in sounded a note of caution Wednesday over the North's offer of denuclearisation talks, saying it was "too early to be optimistic", even as US leader Donald Trump welcomed the development.
President Trump welcomed Pyongyang's breakthrough declaration -- as relayed by Seoul -- that it wanted to talk to the US and would not need nuclear weapons if its security was guaranteed as positive and apparently sincere.
It followed months of tensions, threats and personal insults between him and the North's leader Kim Jong Un, before the Winter Olympics in the South triggered a flurry of diplomacy.
Moon and Kim will sit down for a summit on the southern side of the Demilitarized Zone next month, Seoul said after its envoys returned from a historic trip to Pyongyang.
Kim said the North would halt provocative missile and nuclear tests while talks are under way, it added.
But Moon told party leaders: "We are only at the starting line and it's too early to be optimistic."
"Inter-Korean talks won't be enough to achieve peace," he said, stressing the importance of Seoul maintaining close co-operation with its security guarantor Washington and adding there would be no let-up in sanctions or pressure purely as a result of inter-Korean dialogue.
There have been two previous inter-Korean summits, in 2000 and 2007, both of them in Pyongyang -- although it later emerged the North had been paid $500 million ahead of the first meeting, prompting critics to denounce it as a bribe.
Moon denied there had been any behind-the-scenes agreement with Pyongyang in return for it coming to the negotiating table, adding: "There will be no such a thing as a gift to the North."
Trump was upbeat on the news from Seoul, crediting Washington's "very, very strong" sanctions push, as well as "big help" from China, for the potential diplomatic breakthrough.
"We have come a long way at least rhetorically with North Korea," Trump said.
"We are going to do something, one way or the other, we are going to do something and not let that situation fester."
But he signalled the threat of military action remained on the table should talks fail to make headway, and his administration said it would press ahead with potentially provocative joint war games with South Korea.
China's foreign ministry praised the "positive outcomes" of the meeting in Pyongyang, urging both sides to "seize the current opportunity" to promote the denuclearisation of the peninsula.
But Japanese Chief Cabinet Secretary Yoshihide Suga said there was no change in Tokyo's policy of imposing "maximum pressure" on the North over its nuclear and missile programmes.
Past talks and deals with the North had failed to result in its denuclearisation, he pointed out, after defence minister Itsunori Onodera told reporters: "We still don't know clearly North Korea's intention."
- Munich Agreement -
The North's offer divided opinion in the South Wednesday, with newspapers cautiously welcoming it but the main opposition party drawing parallels with the Munich Agreement that allowed Hitler to annex parts of Czechoslovakia.
"There are positive points in this agreement," the South's conservative Chosun Ilbo daily said in an editorial.
"However, a question mark still hangs over the key issue -- whether the North is genuinely willing to negotiate away its nuclear arsenal," it said.
Hong Joon-pyo, the head of the conservative main opposition Liberty Korea Party, lambasted the talks as akin to the 1938 deal British prime minister Neville Chamberlain negotiated with Adolf Hitler -- and proclaimed as "peace for our time" -- agreeing to Nazi Germany's annexation of the Sudetenland in Czechoslovakia.
"The agreement reminds me of the 1938 Munich Agreement," Hong wrote on his Facebook page. "Only fools would be cheated twice," he added.
The pro-business Joongang Ilbo daily said an inter-Korean summit would be meaningless unless it led to the North's denuclearisation.
The independent Hankyoreh daily was more enthusiastic, welcoming the agreement as "an achievement with great significance that went beyond all expectations".
But the North's state media made no mention of the developments, with the Rodong Sinmun, the mouthpiece of the ruling Workers Party, instead leading on messages of congratulation sent to Kim for the 70th anniversary last month of the founding of the North's military.
In a commentary the paper said that Pyongyang's possession of a nuclear arsenal was justified.
"It was a shining victory for us in our struggle to achieve a parity in power with the US that we have come to develop hydrogen bombs and ICBMs," it said.
"There was no other alternative for us in the highly confrontational situation where we alone have to face the US, the world's largest nuclear-armed state, with our own means."