Defector: 'North Korea sank Seoul's Cheonan warship'
Korean ties take turn for worse in sinking row - watch Sue Lloyd-Roberts' film
Tensions between North and South Korea have escalated ahead of a report by a multinational team into the causes of the sinking of South Korea's Cheonan warship.
Pyongyang has denied responsibility for the tragedy. But Sue Lloyd-Roberts has been speaking to a military defector who claims multiple sources in North Korea have told him otherwise.
I met Lieutenant Im Chun-yong in Seoul, the capital of South Korea, where he defected from the North a decade ago.
Lieutenant Im is in no doubt that the sinking of the South Korean Cheonan warship in March was the result of an attack by the armed forces in which he once served.
The Cheonan navy ship sank after a mysterious explosion ripped it in half
Forty-six sailors were killed or lost in the blast in disputed waters off North Korea.
He heads an organisation in South Korea which represents military defectors to the South, and claims to be in secret contact with former army colleagues in the North.
"I made calls to the North about this incident and actually contacted 11 people - military people, you know, are allowed mobile phones," he told me.
"Two of them said they were not sure and the other nine said it was done by the North."
It is impossible to verify his claims, but Lieutenant Im believes that North Korean leader Kim Jong-il is trying to send a message to both his neighbours in the South and the wider international community.
He also believes the North's recent belligerence is due to its desperate need for aid.
Lieutenant Im now represents fellow military defectors to the South
Until two years ago, the South Korean government pursued a so-called "Sunshine Policy", sending thousands of tonnes of food to the North and encouraging joint business enterprises to bring the two countries closer together.
"For about 10 years, whatever the North demanded, the South responded to it," says Lieutenant Im.
"They received more aid from the South than from China. But now the South don't give a single grain of fertiliser let alone food, because of the nuclear issues."
With North Korea exacerbating tensions by testing nuclear weapons, the Sunshine Policy was brought to an end when a new, more conservative government was elected in the South in 2008.
As the aid dried up, North Korea refused to attend peace talks and has been under pressure to return ever since.
Lieutenant Im believes this has provided a second motive for the attack.
"The USA keeps asking the North to come to the six-nation peace talks. So it [the sinking of the Cheonan] was to show to America that the North is powerful and that they would not be bullied. I think this is what they ultimately wanted to express."
On a war footing
South Koreans have watched the crisis unfold on television, but it is unlikely that there are many in the North - outside the military - who have even heard of the Cheonan.
If the Americans or South Koreans cause any trouble we shall fight back
Captain Choe Song-il
I met Captain Choe Song-il on the northern side of the heavily-fortified, 200-mile-long (322km) demilitarised zone which separates the two countries.
"We have heard about the sunken ship and the rumours connecting it to us, but this is all speculation," he told me.
The captain insisted that any military retaliation would be met with force: "If the Americans or South Koreans cause any trouble we shall fight back."
The Cheonan incident has brought the two countries to one of the most dangerous points since the end of the Korean civil war.
Indeed, a peace treaty was never signed by the two sides at the end of the armed conflict in 1953, meaning North and South Korea are technically still at war.
As I discovered during my visit to North Korea, the country has been on a war footing ever since. A country of 23 million people has a standing army of more than one million.
The few hours of TV every night broadcast a reminder to the people to be on constant alert against a renewed attack from the US or the South, but there was not any mention of the Cheonan incident.
Ironically, it is possible that TV will be the medium through which one of the most immediate reprisals against the North may be felt.
Pyongyang TV filmed the national soccer team's departure for the World Cup finals.
It had been hoping that South Korean television would provide it with a free feed of pictures of the tournament matches as a goodwill gesture, but negotiations have broken down under the strain of the ongoing crisis.
Of course, the South will be considering far more serious sanctions for the sinking of the Cheonan but, for football fans in the North, the incident could prove to be an own goal for North Korea.
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