What little wealth the country has is spent on the military and analysts have spent years trying to keep track of its various missile programmes.

Nuclear programme

The International Institute for Strategic Studies sums up North Korea's nuclear project in one sentence: It is the only means it has to exert influence on major powers.

North Korea established a full-scale nuclear research centre at Yongbyon in the 1960s with the help of the former Soviet Union.

By the 1980s it focused on uranium fabrication and Jane's Defence Weekly predicted that it could have operational weapons by 1994.

Facing mounting international pressure, Pyongyang signed the Nuclear Non-proliferation Treaty in 1985, only to threaten to withdraw in 1993.

After months of tension, it agreed to freeze the programme in exchange for two nuclear reactors built by the United States, South Korea, Japan and the European Union.

Despite high hopes for that deal, it was effectively dealt a killer blow by North Korea's export of missile technology to other so-called "rogue" nations.

Technology

Much of North Korea's rocket technology is based on Soviet-designed Scud missiles.

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It has developed a family of more advanced missiles - the No-Dong One - with a range of up to 1,000 km and, more recently, the Taepo-Dong series which could ultimately have a much greater range.

In 1998, the conclusions of the US commission assessing the ballistic missile threat, known as the Rumsfield report, said that North Korea's missiles "inevitably and inescapably engage the vital interests of the US".

It predicted that North Korea could deploy the truly intercontinental two-stage Taepo-Dong II before the international intelligence community realised.

Within weeks of the report's publication, North Korea test fired the Taepo-Dong I over the Sea of Japan, sending a political shock wave around the region.

No-Dong: Short range

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A prototype ND-I was reportedly identified on a launch pad in May 1990 and research culminated with a launch up to 1,000 km into the Sea of Japan in 1993.

Military analysts believe that North Korea exported the technology to Pakistan and Iran, both of which then carried out further tests.

Suspicions that former Soviet scientists worked on the project gained ground when Moscow prevented more than 60 Russian scientists from leaving for North Korea in October 1992.

Taepo-Dong I: Medium range

North Korea's first two-stage rocket emerged amid reports of an engine test in February 1994.

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Analysts believe that the first stage is based on the No-Dong and the second stage on one of North Korea's variations of the Scud missile.

The international community believes that the controversial 1998 test firing of a "satellite rocket" over Japan in August 1998 was a TD-I, an event which prompted widespread protests.

Taepo-Dong II: Long range?

The Rumsfield report detailed the TD-II a month before the test firing of the TD-I, describing it as a "scaled-up" scud capable of carrying a warhead of up to 1,000 kg.

Western analysts believe that the TD-II could have a range of up to 6,000 km, putting Alaska, Hawaii, China, parts of India and western Russia within its reach.

Raising the stakes

Despite these fears, North Korea's programme may not be as far advanced as thought as it still needs crucial re-entry hardware.

Furthermore, the US State Department's spokesman James Rubin said in June that its team had found no evidence of nuclear production facilities during its agreed inspection of the Yongbyon site.

Mr Rubin said that there was no evidence of an attempt to conceal facilities, though he declined to elaborate on the real purpose of the site.