A US teenager said Friday that he would not give up his campaign for a peace forest on the tense inter-Korean border despite North Korea's negative reaction to his proposal.

Jonathan Lee, a 13-year-old ethnic Korean from Mississippi, said North Korean officials had insisted that a peace treaty should first be signed with South Korea and the United States before they would agree to this.

The Koreas have been technically at war since the 1950-53 conflict ended in a fragile armistice, with no peace treaty signed.

"I was told that unfortunately I wouldn't be able to create the forest until the peace treaty was signed between America and North Korea," he told reporters in Seoul after his week-long trip to the communist country.

"Because Korea is one, maybe there will be a peaceful resolution for the problem eventually and one day the peace treaty will be signed," he added.

Lee and his parents entered Pyongyang last week with a letter for North Korean leader Kim Jong-Il, proposing the creation of a "children's peace forest" in the demilitarised zone (DMZ) dividing the peninsula.

Lee's mother, Melissa, said a North Korean official had conveyed a translated copy of the letter to Kim.

The trip came amid high cross-border tensions, which mounted dramatically after Seoul and Washington accused the North in May of torpedoing a South Korean warship with the loss of 46 lives.

Lee said he could not see Kim, although North Korean officials told him that he had "high chances" of meeting him.

"Maybe next time, I'll try again," he said, adding he felt "safe" during his stay in one of the most secretive states in the world.

He said he was "a little nervous but also sad" when he travelled to the DMZ, which is heavily fortified with concrete, barbed wire, land mines and soldiers on both sides.

Lee said he was encouraged by some North Korean soldiers guarding the DMZ to "hurry up and make the children's peace forest".

His visit recalled the efforts of 11-year-old US schoolgirl Samantha Smith, who in 1983 travelled to the Soviet Union at the height of the Cold War, after writing to then leader Yuri Andropov to ask if he planned a nuclear war against the US.

Lee has sent letters to South Korean President Lee Myung-Bak, US President Barack Obama and China's President Hu Jintao, explaining his idea for the peace forest of fruit and chestnut trees on the world's last Cold War frontier.

In Seoul, the boy is scheduled to participate in a forum organised by the International Union of Forest Research Organisation from August 22 to 28.

earlier related report
US tells Israel Iran is one year from atomic bomb: report
Washington (AFP) Aug 19, 2010 - The United States has persuaded Israel that Iran would take one year or longer to build a nuclear weapon, dimming the prospects of a preemptive strike on Iran's nuclear facilities, The New York Times said late Thursday.

"We think that they have roughly a year dash time," President Barack Obama's top advisor on nuclear issues Gary Samore was quoted as saying in the daily's online edition.

By "dash time," the official referred to the shortest time Iran would take to build a nuclear weapon, judging from its existing facilities and capacity to convert stocks of low-enriched uranium into weapons-grade material, a process known as "breakout."

Samore said the United States believes international inspectors would detect any Iranian move toward "breakout" within weeks, leaving the US and Israel ample time to craft a response.

Israel has hinted in the past that it would likely attack Iranian nuclear facilities should the Islamic republic try to build an atomic bomb it would consider a direct threat to Israeli territory.

Israel believes Iran is only months away from such a scenario, while the US intelligence thinks it would take longer.

Based on intelligence collected over the past year, the new US assessment is not clear on what problems Iran's uranium enrichment program -- which it insists is for peaceful purposes -- is confronting.

The daily said the lag could be due to poor centrifuge design, difficulty in obtaining components or accelerated Western efforts to sabotage the nuclear program.