(CNN) Samoa has declared a state of emergency after several deaths linked to a measles outbreak, closing schools and placing restrictions on public gatherings.

Some 14 children under the age of five and one adult have died from the epidemic in the South Pacific island nation, the United Nations children's agency UNICEF confirmed Tuesday.

The Samoa Ministry of Health declared a measles outbreak on October 16, according to UNICEF , who said there had been more than 1000 suspected cases so far.

Schools have been temporarily shut and children under the age of 17 have been advised by government officials not to attend public gatherings to stop the spread of the disease, UNICEF said.

Measles has seen a wide resurgence around the world -- in both high-income countries in the Americas and Europe and lower-income nations in Asia and Africa -- fueled in part by fear of and lack of access to vaccines, and complacency.

Almost 350,000 measles cases were reported globally in 2018, according to UNICEF -- more than doubling from 2017.

On Monday, Winston Peters, New Zealand's foreign affairs minister, said his country would send vaccination nurses and a medical assistance team of doctors and nurses to Samoa to support the country's immunization program.

"On 15 November the Government of Samoa declared a State of Emergency as the numbers of people infected with measles continues to rise and the hospital system is under strain," Peters said.

"Measles is highly contagious, and the outbreak has taken lives in Samoa. It is in everybody's interests that we work together to stop its spread," Peters said in a separate statement on Friday.

David Durrheim, conjoint professor at the School of Medicine and Public Health at the University of Newcastle in Australia, told CNN affiliate SBS News that Samoa has long had low levels of vaccination.

According to the World Health Organization, roughly 95% of a population needs to be vaccinated with two doses of the measles vaccine to ensure herd immunity.

Measles coverage in Samoa was 40% for the first dose of the vaccine in 2018 and 28% for the second dose, according to UNICEF.

"This latest outbreak in Samoa shows us how important it (is) for vaccination programs to reach children with lifesaving vaccines all over the world," Robin Nandy, UNICEF's chief of immunization, told CNN in a statement.

"We are alarmed that measles cases globally have increased in 2019. This has happened largely due to a combination of conflict, insecurity, a breakdown or interruption in services and mistrust of vaccinations," he added.

In Tonga, another South Pacific nation, the Ministry of Health confirmed an outbreak of measles following the return of Tongan rugby players from New Zealand, where one player developed the illness.

In a report released on Wednesday, the ministry said 251 cases of confirmed or suspected measles have been identified.