Cape Town – New Zealand Prime Minister John Key says at least 2 people were killed in powerful earthquake that struck the island early on Monday morning.Residents in coastal areas fled through the night Monday after the 7.8 earthquake struck just after midnight, triggering a potentially destructive tsunami, AP reported.Nearly seven hours after the first quake struck, the prime minister confirmed two fatalities, saying "we cannot rule out" that number will rise."At this point we are unable to give precise details of what caused those fatalities," Key said, adding that communication problems made it difficult to get information from the affected areas of the South Island.The earthquake, centred north of Christchurch in the South Island, was felt throughout the country, causing widespread damage and reported casualties.Authorities said they were not yet declaring a national emergency, saying the regions are coping well.- Are you there? Send us your eyewitness accounts and photos“It was an unbelievable experience to feel how the structure of your house bends, turns and creaks underneath you,” Jan-Harm Steenkamp, a South African working in Christchurch, described the experience.“The quake struck at about 00:15 and woke us up. Alarms when off all around us and the entire neighbourhood was outside. Everyone wanted to know if we were OK,” he told News24.He said they were far enough from the epicentre to not be too badly affected, but would assess the damage as the day goes on.According to AP, authorities in Wellington are urging people who work in the centre of the city to stay home on Monday.City officials said some large buildings were showing signs of structural stress and that the quake would like have caused damage to some buildings.The city's suburban rail network was shut while crews checked tracks, bridges and tunnels.Authorities in New Zealand downgraded tsunami warnings around the country following a powerful earthquake just after 20:00.