North Korean leader Kim Jong Un gives field guidance at the newly built Wisong Scientists Residential District. (Reuters)
North Korea said Saturday it had offered to "temporarily" suspend any future nuclear test if the United States cancels its annual joint military drills with South Korea this year.
The government proposal was passed to the US side through a "relevant channel" on Friday, the North's official KCNA news agency said.
The message called on Washington to help ease tensions on the Korean peninsula by suspending all of this year's joint military exercises in South Korea "and its vicinity".
For its part, North Korea "is ready to take such a responsive step as temporarily suspending the nuclear test over which the US is concerned," it said.
The United States, which has close to 30,000 troops permanently stationed in South Korea, conducts a series of joint military exercises with its key Asian ally every year.
Seoul and Washington insist the drills are defensive in nature, but they are regularly condemned by Pyongyang as provocative rehearsals for invasion.
The annual exercises habitually raise military tensions between the two Koreas, who have remained technically at war since the 1950-53 Korean War concluded with a ceasefire rather than a peace treaty.- 'Anniversary' proposal -
The KCNA report said Pyongyang's proposal was aimed at de-escalating tensions in 2015 which marks the 70th anniversary of the initial division of the Korean peninsula into North and South following the 1945 Allied victory in World War II.
Describing the US-South military drills as the "root cause" of tensions on the peninsula, KCNA said their continuation precluded any possibility of dialogue or detente.
Should Washington require talks to clarify Pyongyang's new proposal, the North "is ready to sit with the US anytime," the agency said.
North Korea has conducted three nuclear tests -- the last in February 2013 and recently threatened a fourth in response to a UN resolution condemning its human rights record.
However, expert analysis of recent commercial satellite images of the North's main underground test site have shown none of the activity associated with a pending detonation.
North Korea perennially demands that the US and South Korea cancel their drills, but analysts said the offer of a quid pro quo on nuclear testing suggested a more pragmatic approach.- Will Washington bite? -
"It's like they're putting a worm on a line to see if they can get a nibble," said John Delury, a North Korea expert at Yonsei University in Seoul.
"But I don't see the US biting, at least not publicly," he added.
Washington has steadfastly refused to consider any dialogue with Pyongyang until the North shows a tangible commitment to abandoning its entire nuclear weapons programme.
Both Washington and Seoul have cursorily dismissed all previous demands to halt their joint drills.
And any apparent US concession towards Pyongyang will be politically difficult at the moment, given the particularly strained atmosphere in the wake of the recent high-profile cyber attack on Sony Pictures which Washington blamed on North Korea.
"I imagine the State Department will publicly slap down this proposal, but it could stir some internal debate, especially among those seeking a fresh approach to North Korea in the last two years of the Obama administration," Delury said.
Writing this week in the Bulletin of Atomic Scientists, a leading expert on North Korea's nuclear programme, Siegfried Hecker, estimated that the North likely had 12 nuclear weapons, with an annual manufacturing capacity of four to six more devices.
"So, by the time (President Obama) leaves office, North Korea may have conducted another nuclear test and have an arsenal of 20 bombs," Hecker warned.