Wellington: At least two people were killed on Monday after a series of powerful earthquakes jolted New Zealand's South Island, triggering a tsunami and sending aftershocks across the country, officials said.
The first, a 7.8-magnitude quake, struck just after midnight on Monday near the coastal community of Kaikoura, some 93 km northeast of the city of Christchurch, the US Geological Survey reported.
It triggered waves of 8 feet above usual tide levels, the highest New Zealand had seen in at least 38 years, Philip Duncan of Weather Watch New Zealand said.
An initial tsunami warning was lifted but temblors continued on Monday afternoon, CNN reported.
A 6.2-magnitude quake struck around 1.30 p.m., km west-southwest of Kaikoura, further north of Christchurch.
Aftershocks from South Island reverberated all the way to Wellington, the country's capital on the North Island, where residents were told to stay indoors Monday.
Images on social media showed shattered windows, toppled grocery items on the floor of a supermarket and water sloshing back and forth in swimming pools from different parts of the country.
Prime Minister John Key called off talks in Buenos Aires, Argentina scheduled for Tuesday following the quakes, Xinhua news agency reported.
"The situation is still unfolding and we don't yet know the full extent of the damage," Key said in a statement.
The South Island was hit by a flurry of aftershocks, according to the USGS and New Zealand's Geonet service, some with a magnitude above 6.0.
Officials from the island's second-largest town, Dunedin, has issued a state of emergency.
New Zealanders are used to earthquakes. The country lies on the Ring of Fire, the line of frequent quakes and volcanic eruptions that circles virtually the entire Pacific rim, the BBC reported.
Christchurch is still recovering from a 2011 earthquake that killed 185 people and destroyed the city centre.