Strong earthquakes have rocked central New Zealand, damaging homes, destroying a bridge and sending office workers scrambling for cover in the capital, Wellington.
No serious injuries were reported in the magnitude-6.5 quake, which hit after 2:30pm on Friday near the northern tip of New Zealand's South Island.
It was dangerously shallow at a depth of about 8km, similar to a deadly tremor that shattered the South Island city of Christchurch two years ago.
There were at least six aftershocks that were of 5.0 magnitude or stronger.
Several homes near the epicentre were severely damaged, with chimneys collapsing and roofs caving in, Barbara Dunn, a police spokeswoman, said.
She said a bridge was severely damaged on the main highway near the town of Seddon, and that rocks and debris had fallen onto the road.
Police closed a section of the highway.
Some buildings in Wellington were evacuated, and items were knocked off shelves in places.
Police said a number of people were freed from Wellington elevators that stopped working.
Air, rail and bus services were suspended while officials checked tracks, runways and roads for damage, and trading on New Zealand's NZX stock exchange was halted temporarily.
There were also widespread power outages across the north of the South Island.
The US Geological Survey said the epicentre of the initial quake was 94km west of Wellington at a depth of 10km.
The Geological Survey originally measured the quake with a magnitude of 6.8 but later revised that figure down to 6.5.
New Zealand quake monitoring service GNS Science put the magnitude at 6.2.
Caroline Little, a seismologist with New Zealand quake monitoring agency GeoNet, said the series of quakes since July had followed an unusual pattern.
"Normally you get a big quake and then the aftershocks get smaller in magnitude," she said.
Little said the July quake was on a fault line near Seddon that had not previously been mapped.
She said it was too early to determine if Friday's quakes were on that same fault.
A different fault line runs through Wellington, and many in the city fear a major disaster if it were to become active.
New Zealand has been hit by a string of quakes since a shallow, 6.3 magnitude tremor devastated the Canterbury region in 2011, killing nearly 200 people and causing $30bn in damage to Christchurch, the country's second largest city.
Earthquakes are common in New Zealand, whose two islands lie along the Australia-Pacific tectonic plate boundary.
The country is part of the so-called Pacific Ring of Fire that has regular seismic activity.