New Zealand quake: Christchurch shocked by tremors

Christchurch in New Zealand has been hit by a series of earthquakes, the largest reaching magnitude six, four months after a quake that killed 181 people.

Officials say two people have been rescued from a collapsed church and several were injured by falling masonry.

There are reports of boulders tumbling down hillsides, and in places the ground liquified.

The city's mayor, Bob Parker, said people there were "very nervous, very concerned".