Watchful Obama warns North Korea

US President urges Pyongyang to cancel its plans to fire a long-range rocket next month

US President Barack Obama peered through his binoculars into North Korea on a first visit to its tense border with the South yesterday, and then returned to Seoul to give a clear warning of real consequences if Pyongyang presses ahead with plans to launch a long-range rocket next month.

Although the talk was carefully vague, Mr Obama strongly hinted that the US would hold back on 240,000 tons of emergency food aid as promised in "the leap year agreement" reached between US and North Korean envoys on February 29 in Beijing. At the time, North Korea promised a moratorium on testing of long-range missiles as well as nuclear warheads. "It would be difficult," said Mr Obama, "to move forward with that package if they showed themselves unable to meet commitments even a month later."

Here for a two-day nuclear security summit with leaders from more than 50 nations and international agencies that starts today, Mr Obama stood beside South Korea's President Lee Myung-bak in a show of solidarity to underline worries about the test. The US and South Korean presidents used rhetoric rather than specific threats, however, to dissuade Pyongyang from firing the rocket, which North Korea says is to launch a satellite, not to perfect a missile with a theoretical range as far as the west coast of the US. "We've presented to them an opportunity to take a different path from the one they are taking," Mr Obama said. "They need to understand that bad behaviour will not be rewarded."

Mr Obama indicated he would appeal to China's President Hu Jintao to do more to get the North to cease and desist. "The question is what the Chinese are doing," the US President said.

His visit to the demilitarised zone between the Koreas said as much as his words in reaffirming US commitment to the Korean peninsula. On the basis of his observations across the line, Mr Obama said North Korea was "like a time warp, a country that missed 40 to 50 years of progress" and was unable "to deliver any indicators of well-being for its people". He seemed intensely curious about what he was seeing, asking about a village several miles inside North Korea and the route of the line between the two Koreas.

Just south of the line, he chatted with US troops sharing duties with South Koreans in and around the truce village of Panmunjom, where the Korean War armistice was signed in July 1953.

"I could not be prouder of what you're doing," he said to about 50 of them, the vanguard of 28,500 American soldiers still in South Korea. "You guys are at freedom's frontier."

While he was there, reports circulated here that North Korea was transporting its rocket by train to the launch site. The prospect of a cancellation of Pyongyang's plans appeared remote, considering it is slated to come against the backdrop of massive observances on 15 April of the 100th anniversary of Kim Il-sung, the founding leader and grandfather of Kim Jong-un, who took over in December after his father, Kim Jong-il, died.

"The situation remains unsettled," said Mr Obama. "It's not clear who's calling the shots." Whoever's really in charge, the President surmised, "they have not yet made that strategic pivot where they say what they're doing is not working."