US fears 'hell' of a response

PLANS previously drafted by the Pentagon predict 52,000 US military casualties and one million civilian dead in the first 90 days of conflict if America attacked Pyongyang.

The US leadership is looking at international economic and diplomatic sanctions against North Korea as its primary response to Monday's nuclear test.

But military contingencies are considered as a matter of course and analysts paint a horrific picture for even the most targeted of US strikes.

A report this week by US-based security and military analyst Stratfor predicts North Korea could return fire on Seoul with "several hundred thousand high-explosive rounds per hour" -- with up to 25 per cent of shells filled with nerve gas.

Other estimates say the US would need at least 500,000 ground troops to secure against a North invasion of the South.