Vanuatu warned Tuesday it faces imminent food shortages as accounts emerged of huge damage to a large outer island, days after one of the fiercest cyclones on record pummeled the Pacific archipelago.

Relief agencies say conditions are among the most challenging they have faced, with concerns mounting that disease and a lack of clean water could add to the current toll of 24 confirmed fatalities.

Relief supplies began arriving in cyclone-devastated Vanuatu Sunday as the Pacific nation declared a state of emergency amid reports entire villages were "blown away" when a monster storm swept through.

The official death toll in the capital Port Vila stood at six, although aid workers said this was likely just a fraction of the fatalities nationwide.

Tropical Cyclone Pam triggered flooding along with evacuation orders affecting thousands of people in Vanuatu on Friday as it intensified to a maximum-strength storm offshore, officials said.

Aid agencies said many people living in flimsy slum accommodation were particularly at risk in the poor Pacific nation of 270,000 people, as well as those in remote outlying islands.

Vauatu was battening down Thursday as a powerful cyclone that forecasters warn will pack winds in excess of 165 kilometers an hour (102 mph) threatened the capital Port Vila.

Tropical Cyclone Pam was intensifying as it approached land and set to become a maximum category five system, Fiji's Tropical Cyclone Warning Center said.

A 6.5-magnitude earthquake struck off the Pacific nation of Vanuatu Thursday, the United States Geological Survey said.

The USGS reported that the quake hit at a depth of 10 kilometers (6.2 miles) about 149 kilometers from Vanuatu's capital Port Vila.

A powerful 6.8-magnitude earthquake struck off the Pacific nation of Vanuatu Friday, the United States Geological Survey said, but no tsunami threat was detected.

The quake hit at a depth of 218 kilometres (135 miles) about 84 kilometres from Vanuatu's capital Port Vila, the USGS said.

Two people were confirmed dead and another two were missing after an inter-island ferry sank in the Pacific archipelago of Vanuatu on Friday, with survivors forced to endure more than six hours adrift, officials said.

The ferry carrying 30 passengers and 13 crew sank in the early hours of the morning as it was sailing from Malekula to the capital Port Vila, Vanuatu Red Cross chief executive Jacqueline De Gaillande said.

A powerful 6.6 magnitude earthquake struck Wednesday off the coast of Vanuatu in the South Pacific, but U.S. geologists said it was too deep to cause a tsunami.

The U.S. Geological Survey said the quake struck at 1603 GMT about 37 kilometers (23 miles) west of Sola, Vanuatu.

A 6.2-magnitude quake hit off the South Pacific island of Vanuatu on Friday, the U.S. Geological Survey said, but it was not expected to generate a tsunami.

The US Geological Survey said the tremor at 0707 GMT was 135 kilometers (84 miles) deep and some 48 kilometers northeast of Luganville, and more than 270 kilometers from the capital Port Vila.

A 6.7-magnitude earthquake struck in the South Pacific near Vanuatu and New Caledonia's Loyalty Islands on Friday, the U.S. Geological Survey said.

The quake struck at a depth of 32 kilometers at 07:09 GMT, around 60 kilometers northeast of Isangel in Vanuatu and 325 kilometers from Tadine in the French Pacific territory of New Caledonia, according to USGS.