Watch part two
North and South Korea are still technically at war but since the armistice of 1953, that has largely been a battle of words.
In 1998, South Korea's then president, Kim Dae Jung announced the "sunshine policy" which emphasised peaceful co-operation with the North and eventual reunification.
There followed almost a decade of optimism. But when the North reportedly tested a nuclear weapon in late 2006, things started to deteriorate once more.
Now relations on the Korean Peninsula appear to be souring further, fuelled by political change in South Korea.
On April 9, Lee Myung-bak's conservative Grand National Party secured a majority in the South's parliamentary elections.
With a solid platform in parliament, the new president decided he had a mandate to take a new line against North Korea.
President Lee got tough, insisting aid to the North should be linked to its denuclearisation.
That stance prompted a firestorm of angry rhetoric from the North, with Pyongyang threatening to reduce Seoul to ashes with a pre-emptive strike.
101 East asks just how serious is this latest escalation between the two Koreas.
Host Teymoor Nabili is joined by Song Young-Sun, a member of South Korea's parliamentary assembly, and Professor Richard Broinowski, a former Australian ambassador to Seoul.
This episode of 101 East aired on Thursday, April 24, 2008.
Source: Al Jazeera