A strong earthquake measuring 8.0 on the Richter scale struck the Pacific island nation of Samoa on early Wednesday with at least 19 people killed by tsunami after the earthquake.

The quake, occurred at 6:48 a.m. Samoa local time (17:48 GMT Tuesday), was centered 195 km south of the Samoa capital of Apia with a depth of 18 km.

Five people in Samoa were confirmed to have been killed by a tsunami following the quake, Radio New Zealand International reported on Wednesday.

A spokesperson for New Zealand's foreign minister said five people have died and others have been swept out to sea by the tsunami and are still unaccounted for.

In neighboring American Samoa, the tsunami has caused some deaths. Local radio in American Samoa reported 14 deaths.

A tsunami warning had been issued by the Hawaii-based Pacific Tsunami Warning Center.

The warning covers Samoa, American Samoa, New Zealand, Niue, Wallis-Futuna, Tokelau, Cook Islands, Tonga, Tuvalu, Kiribati, Kermadec Islands, Fiji, French Polynesia, Howland-Baker, Jarvis Is and Palmyra Is.

Xie Yancun, a diplomat from the Chinese Embassy to Samoa, told Xinhua by phone that the strong quake jolted him awake, he evacuated from the house immediately. Then, he experienced aftershocks. Later he found some items dropped on the floor in his office.

Xie said it was a very strong quake and many local people have been evacuated to higher ground in Apia following the tsunami warning.

The quake lasted as long as a minute-and-a-half, the spokesman for the national disaster office of Samoa said, and people in the capital Apia were continuing to experience aftershocks.

The Tsunami Warning Center said the tsunami had been observed at Apia, Samoa, and at Pago Pago, in American Samoa.

The waves at Pago Pago were as high as 1.57 meters above normal sea level.

There was a red alert in French Polynesia as a tsunami is expected to hit shortly.

A two-meter wave is expected to hit the Marquesas islands while a 90 centimeter wave is forecast for the Society island and the Tuamotus.

On the island of Nukunono in Tokelau, preparations are under way in case any big waves arrive after the earthquake.

In New Zealand, the Civil Defense has issued a warning for all of New Zealand.

The head of Civil Defense in New Zealand, John Hamilton, said the ministry has alerted the country's emergency groups and has activated the National Crisis Management Center.

It advises people to listen to broadcasts on radio from local civil defense authorities and local emergency services.

It does not expect New Zealand to experience the same impact as Samoa, but people in coastal areas, especially on eastern and northern coasts, should be ready to be evacuated promptly if they are told to.

Three other quakes have been felt in the region.

A magnitude 5.6 earthquake hit the same area following the 8.0 magnitude earthquake, the United States Geological Survey said.

Another quake of 5.6 magnitude struck the northern Cook Islands region and the Tonga region was rattled by a 5.8 magnitude quake after the 8.0 magnitude earthquake.