Japan earthquake: 'Fighting an enemy you cannot see'

Radioactive water is leaking into the sea from a 20-centimetre (8-inch) crack in a containment pit at Japan's quake-hit Fukushima nuclear plant, its operator Tepco has said.

The crack under reactor 2 may be the source of recent radiation in coastal waters, Tepco officials said.

'You are fighting an enemy you cannot see', Japanese PM Naoto Kan told relief workers as he visited areas of northern Japan devastated by the earthquake.

Rachel Harvey reports.