From BBC - News Local/State -

North Korea ‘Readies Rocket Force’ After US Stealth Flights

Kim Jong Un

In this undated photo released by the Korean Central News Agency (KCNA) and distributed Thursday, March 14, 2013 by the Korea News Service, North Korean leader Kim Jong Un uses a pair of binoculars to watch live ammunition firing drills by the Jangjae Islet Defense Detachment and the Mu Islet Hero Defense Detachment deployed in the southwestern sector in North Korea. (AP Photo/KCNA via KNS)

North Korea says it has put missile units on stand-by to attack US targets in response to US stealth bomber flights over the Korean peninsula.

State news agency KCNA said leader Kim Jong-un signed off on the order at a late-night meeting of top generals.

The time had come to "settle accounts" with the US, KCNA quoted him as saying, with the B-2 flights an "ultimatum".

Pyongyang has been angered by fresh UN sanctions and annual US-South Korea military drills.

"If they make a reckless provocation with huge strategic forces, the Korean People's Army (KPA) should mercilessly strike the US mainland, their stronghold, their military bases in the operational theatres in the Pacific, including Hawaii and Guam, and those in South Korea," KCNA quoted Kim Jong-un as saying.

Kim Jong-un "finally signed the plan on technical preparations of strategic rockets of the KPA, ordering them to be stand-by for fire so that they may strike any time", the report added.

A Yonhap news agency report citing an unidentified military official said increased activity had been noted at North Korea's missile sites, but this remains unconfirmed.

The US - which flew two stealth bombers over the peninsula on Thursday as part of the ongoing military drills - has said it is ready for "any eventuality" on the peninsula.

In a statement, it said that the B-2 planes demonstrated America's ability to "provide extended deterrence" to its allies and conduct "long-range, precision strikes quickly and at will".

"The North Koreans have to understand that what they're doing is very dangerous," US Defence Secretary Chuck Hagel told reporters on Thursday. "We must make clear that these provocations by the North are taken by us very seriously and we'll respond to that."

The US flew nuclear-capable B-52 bombers over South Korea earlier this month, in what it called a response to escalating North Korean threats.

Unprecedented rhetoric

Tensions in the Korean peninsula are high following North Korea's third nuclear test on 12 February, which led to the imposition of a fresh raft of sanctions.

North Korea has made multiple threats against both the US and South Korea in recent weeks, including warning of a "pre-emptive nuclear strike" on the US and the scrapping of the Korean War armistice.

North Korea is not thought to have the technology to strike the US mainland with either a nuclear weapon or a ballistic missile, but it is capable of targeting some US military bases in Asia with its mid-range missiles.

While North Korea has issued threats against the US and South Korea in the past, this level of sustained rhetoric is unusual, observers say.

On 16 March, North Korea warned of attacks against South Korea's border islands, and advised residents to leave the islands. In 2010 it shelled South Korea's Yeonpyeong island, causing four deaths.

On Wednesday, Pyongyang also cut a military hotline with the south - the last direct official link between the two nations.

A Red Cross hotline and another line used to communicate with the UN Command at Panmunjom have already been cut, although an inter-Korean air-traffic hotline still exists.

China, North Korea's biggest trading partner, has called for calm from all sides.

Speaking at a press conference on Tuesday, Chinese Foreign Ministry spokesman Hong Lei said he hoped all "relevant parties [would] exercise restraint so as to ease the tension".