300 still missing in Christchurch quake (UPDATES) (VIDEO)

The death toll from Tuesday's earthquake in Christchurch, New Zealand, rose to 75 as Prime Minister John Key declared a national state of emergency and search and rescue teams prepared for a second night of operations.

Rescue workers pulled 48 bodies from the rubble of collapsed buildings Tuesday night, but more than 300 people remain missing.

The 6.3-magnitude quake struck hit close to the surface of the earth just before 1 p.m. Tuesday as the south island city was at its busiest.

Authorities worked to conduct rescue operations Tuesday and Wednesday. "There is incredible carnage right throughout the city," Police Superintendent Russell Gibson told BBC. "There are bodies littering the streets, they are trapped in cars and crushed under rubble."

"We are getting texts and tapping sounds from some of these buildings and that's where our focus is," he added.

More than 500 search and rescue personnel, fire and police officers and volunteers worked to find survivors and recover victims throughout Tuesday night.

They might have to continue working through a second night as well, according to civil defense national controller David Coetzee.

He said the search and rescue teams are now focused on 10 buildings considered critical where people could be trapped.

The quake caused widespread damage throughout Christchurch, the second largest city in New Zealand. Australian companies estimate the damage will cost $12 billion.

"This event is particularly devastating, given the region is still rebuilding following the previous major earthquake, in September 2010," said Insurance Australia Group chief executive Mike Wilkins in a statement on Wednesday, according to the Wall Street Journal.

A 7.1 quake hit the area in September but caused no casualties.

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