U.S. Secretary of State John Kerry arrived in South Korea on Friday on an unusual diplomatic journey, traveling directly into a region bracing for a possible North Korean missile test and risking that his presence alone could spur Pyongyang into another headline-seeking provocation.

Kerry was kicking off four days of talks in East Asia amid speculation that the North's unpredictable regime would launch a mid-range missile designed to reach as far as the U.S. territory of Guam. Kerry also planned to visit China and Japan.

North Korea often times its provocations to generate maximum attention, and Kerry's presence in Seoul will provide plenty of that, even if the United States is engaged in intense diplomacy with China, the North's benefactor, in an effort to lower tensions. Another dangerous date on the calendar is April 15, the 101st birthday of North Korea's deceased founder, Kim Il-sung.

Kerry's trip coincides with the disclosure of a new U.S. intelligence report that concludes North Korea has advanced its nuclear knowhow to the point that it could arm a ballistic missile with a nuclear warhead. The analysis, disclosed Thursday at a congressional hearing in Washington, said the Pentagon's intelligence wing has “moderate confidence'' that North Korea has nuclear weapons capable of delivery by ballistic missiles but that the weapon would be unreliable.

Pentagon spokesman George Little said afterward that “it would be inaccurate to suggest that the North Korean regime has fully tested, developed or demonstrated the kinds of nuclear capabilities referenced'' at the congressional hearing.

James Clapper, the director of national intelligence, said he concurred with Little and noted that the report alluded to at the hearing was compiled by the Pentagon's Defense Intelligence Agency and was not an assessment by the entire U.S. intelligence community.  “Moreover, North Korea has not yet demonstrated the full range of capabilities necessary for a nuclear armed missile,'' he said.

President Barack Obama on Thursday urged calm, calling on Pyongyang to end its saber-rattling while sternly warning that he would “take all necessary steps'' to protect American citizens.

Kerry's trip marks his first foray to the Asia-Pacific as America's top diplomat, spearheading the effort to “pivot'' U.S. power away from Europe and the Middle East and toward the world's most populous region and fulcrum of economic growth.

And it comes on the heels of months of provocative action and warlike rhetoric from Pyongyang, including talk of nuclear strikes against the United States _ however outlandish analysts consider such threats. No one is discounting the danger entirely after tests of a nuclear device and ballistic missile technology in recent months.

Kerry's trip was planned well in advance of the latest danger to destabilize the Korean peninsula: North Korea's apparent preparations for another missile test in defiance of United Nations resolutions. The crisis clearly has overtaken the rest of his Asian agenda.

The Obama administration believes North Korea is preparing for another missile test, said a senior State Department official traveling with Kerry on the plane to Seoul. “We will show to our allies that we are prepared and we will defend them,'' the official said.

To mitigate the threat, however, Kerry is largely depending on China to take a bigger role in pressuring North Korea to live up to previous agreements to halt its nuclear and ballistic missile programs. It's a strategy that has worked poorly for the U.S. for more than two decades.

Beijing has the most leverage with Pyongyang. It has massively boosted trade with its communist neighbor and maintains close military ties. And the U.S. believes the Chinese could take several specific steps to show North Korea it cannot threaten regional stability with impunity.

These include getting China to cut off support for North Korea's weapons of mass destruction program, said the State Department official and another senior administration official, though they rejected that the U.S. was seeking a commercial embargo against the North.

The officials spoke on condition of anonymity because they weren't authorized to speak publicly about Kerry's meetings in advance.

Neither could say, however, whether Pyongyang under its enigmatic young leader, Kim Jong Un, was actually listening at this point. One of them stressed that he “wouldn't say there is no conversation between them,'' but declined to describe the level and impact of Chinese-North Korean contacts.

Kim's actual control of the country also is unclear, the official added. Now 29 or 30, the basketball devotee and product of a Swiss boarding school inherited power from his late father, Kim Jong-il, some 16 months ago and has seemed to lead his country on an increasingly reckless path toward possible confrontation.

That has led many observers and policymakers abroad to devote increasing time toward analyzing what little information they have on Kim to figure out how he can be mollified without being rewarded. (AP)