After months of rising tension, the United States is gingerly exploring how to launch talks with North Korea without loosening the screws on the isolated state, experts say.

President Barack Obama has made dialogue a hallmark of his foreign policy, extending a hand to regimes no matter how odious in US eyes. A major exception was North Korea, which since Obama took office has tested a nuclear bomb and allegedly torpedoed a ship in the deadliest inter-Korean incident in decades.

The United States has kept up the pressure, on Monday slapping sanctions against North Korean entities including its military intelligence bureau. But a growing number of US officials and analysts, even hawks, say talks have been moribund for too long.

"If you're whacking one end of the donkey with a stick, it's good periodically to check on the other end to see if the donkey has changed its behavior," said Bruce Klingner of the conservative Heritage Foundation.

Secretary of State Hillary Clinton on Tuesday conferred with former president Jimmy Carter, who visited North Korea last week to secure the release of an imprisoned American teacher.

Top negotiators from China and South Korea are also visiting Washington this week to meet with senior US officials. North Korea's leader Kim Jong-Il just paid a five-day visit to China, his regime's main supporter.

Surprising many observers, Kim did not meet Carter, who helped broker an end to a 1994 crisis in North Korea. But the former president met with number two leader Kim Yong-Nam, who voiced support for resuming six-nation nuclear disarmament talks.

State Department spokesman Philip Crowley said North Korea must first end "provocative and belligerent behavior" and comply with a 2005 agreement reached during six-way talks, in which Pyongyang committed to ending its nuclear program in return for aid and security guarantees.

"If we see evidence that North Korea is prepared to move in that direction, then we are open to further engagement," Crowley told reporters.

North Korea has repeatedly voiced willingness to return to the table but insisted that the United States recognize it as a nuclear power.

L. Gordon Flake, executive director of the Mansfield Foundation, said that North Korea needed to moderate its stance if it truly wanted talks, as otherwise the United States feared legitimizing its claim as a nuclear power.

"The United States does need some kind of fig leaf," said Flake, who advised Obama when he was a presidential candidate.

But few expect breakthroughs at a delicate moment in North Korea, where experts say Kim Jong-Il is preparing a power transfer to his young son Kim Jong-Un and an already dire economy has been thrown into havoc by a ham-fisted currency revaluation.

Michael Green, who served as the top Asia adviser to former president George W. Bush, expected that talks would begin within months but that the Obama administration would insist on a broad agenda.

"The consensus that's probably emerged is that we need contact with North Korea," said Green, now a scholar at Georgetown University and the Center for Strategic and International Studies.

"If we have a policy that is only made up of sanctions, military exercises and pressure," Green said, "you do run some risk of pushing Pyongyang into a corner."

"At a time of potentially profound change within North Korea, you lose some opportunities to gauge and test where things are headed," Green said.

He added that the administration appeared determined not to accept North Korea's demands to ease sanctions in exchange for talks.

But Green said the United States has also sidestepped calls from hawks in South Korea for a more robust response to the March sinking of the Cheonan corvette, which killed 46 sailors.

"Like Goldilocks and the Three Bears, the administration got it about right -- not too hot, not too cold," he said.

earlier related report
Japan says 'too early' to resume N. Korea nuclear talks
Tokyo (AFP) Aug 31, 2010 - Japan said Tuesday it was too early to resume stalled six-party talks on North Korea's nuclear disarmament following the sinking of a South Korean warship which has stoked tensions in the region.

Foreign Minister Katsuya Okada made the comments during a visit to Tokyo by China's envoy Wu Dawei, who has been promoting a resumption of the negotiations which have been stalled since April 2009.

"Even if North Korea is positive about a return to dialogue, it is North Korea itself which created the current environment," Okada said after holding talks with Wu, who has also visited Pyongyang and Seoul this month.

"Considering the way South Korea views the sinking of the military vessel, it is too early to reconvene six-way talks," he said.

North Korean leader Kim Jong-Il, who returned from a visit to China on Monday, told President Hu Jintao he was willing to return to the nuclear forum and reduce tensions, according to Chinese state television.

Wu said in Seoul last week that the North supported China's three-step proposal to revive the talks, which have been frozen since Pyongyang walked out in April 2009 and the next month conducted its second nuclear test.

"Wu said it is important to create an environment for an early resumption of the six-party talks with diplomatic efforts by the countries concerned," Japan's foreign ministry said in a statement.

"He said North Korea hopes to return to political dialogue."

Tensions have been running high on the peninsula since the March sinking of South Korean warship the Cheonan with the loss of 46 sailors which has been blamed by Seoul and Washington on a North Korean torpedo attack.

Japan's Kyodo News agency quoted Wu as telling reporters in Tokyo: "It is necessary to hold discussions with the countries concerned" in the forum -- which groups the two Koreas as well as China, Japan, Russia and the United States.

"We would like to listen to the opinions of each country."

The Japanese foreign ministry said Wu told Okada that "rising tension on the Korean peninsula is undesirable for the peace and stability of its neighbouring countries and North East Asia."

Chinese state media said Tuesday that the United States, Japan and South Korea should not "bully" Pyongyang if they want to ease the friction.

On Monday, the United States slapped new sanctions on the North in the form of asset freezes and travel bans, stepping up the pressure against the reclusive communist regime.