(CNN) -- A 6.3-magnitude earthquake ripped through Christchurch, New Zealand, on Tuesday afternoon, causing multiple fatalities as it toppled buildings onto buses, buckled streets and damaged cathedrals, authorities said. New Zealand Police announced on the agency's website that a large-scale evacuation of the central city was under way. According to the news release, the earthquake killed an undetermined number of people at various locations around the city, including passengers on two buses crushed by buildings that had fallen on them. TVNZ reported that the 147-year-old Christchurch Cathedral's spire had toppled, Christchurch Hospital was being evacuated and the airport was closed.
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NEW: Police say the 6.3-magnitude earthquake caused "multiple fatalities"
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NEW: Large-scale evacuations of central Christchurch are under way
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NEW: Witness describes "windows blowing out, bricks falling down, people screaming"
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The city's Catholic and Anglican cathedrals are damaged; Christchurch airport is closed
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