New Zealand's second largest city, Christchurch, laid in ruins Tuesday, devastated by a massive earthquake that toppled tall buildings and churches during a busy workday. The quake killed at least 65 people and many more were missing.

More than 100 people, including as many as 12 visiting Japanese students, were thought to be trapped underneath rubble as drizzling rain fell on the city at nightfall. A visibly shaken Prime Minister John Key said the world may well be witnessing "New Zealand's darkest day."

Rescue crews with sniffer dogs fanned out across the city in search of survivors, some of whom sent desperate text messages and made cell phone calls from under the wreckage of the 6.3 magnitude quake.

Television footage showed several multistory buildings that fell in on themselves or into the streets, as well as the collapse of the Christchurch Cathedral, whose stone spire crumbled into a city square. Rescue workers say they believe people were in the tower at the time. Helicopters were seen fighting fires and plucking stranded workers from the roofs of high-rise office towers., VOA reported.