International aid agencies ramped up appeals for cyclone-hit Vanuatu on Wednesday, warning that the powerful storm which affected more than two-thirds of the South Pacific island nation had wiped out crops and destroyed fishing fleets, raising the risk of hunger and disease.

Residents of the southern island of Tanna said food and basic supplies were running low while relief workers were still battling to reach many islands pummeled by Cyclone Pam's gusts of more than 185 mph on Friday and Saturday.

The United Nations said the official death toll was 11, but many officials anticipate that number will rise once they are able to more thoroughly inspect the outer islands of the scattered archipelago.

Sweden said on Tuesday a Swedish man aged around 80 who had emigrated was among the dead.

"We are extremely concerned for the safety and well-being of many communities affected by the cyclone, particularly in the more remote regions of the country that are only accessible by boat," said Aurélia Balpe, regional head of the International Federation of Red Cross and Red Crescent Societies (IFRC).

"For a small nation like Vanuatu this is a huge disaster that requires an international response."

Sune Gudnitz, Pacific head of the U.N. Office for the Coordination of Humanitarian Affairs, said food supplies were a concern.

"The challenge of getting things out, whether it's people or goods, remains. We want to avoid creating a bottleneck in Port Vila so we very quickly need to work out a plan for getting things out," Gudnitz said, referring to the Vanuatu capital.

The U.N.'s World Food Program said it was working with aid agencies on the ground to help distribute food and other aid after banana, coconut and other crops were destroyed, livestock was killed and boats and fishing canoes wrecked.

The U.N. Children's Fund (UNICEF) said the government was kicking off a measles prevention campaign because of low immunization rates.

Tourism, which accounts for about 40 percent of Vanuatu's economy, has also been badly affected, with Port Vila closed to cruise liners indefinitely.