Park Director Tran Van Thang said on Wednesday that they were intensifying measures to protect the park from fire, including closing it to visitors.

"We've assigned more teams to prevent illegal entry into the park," he said, adding that the park’s closure started on March 15 and would last until further notice.

Thang said the dry season in April was particularly severe due to the effects of the El Nino phenomenon, with prolonged hot weather, low water levels in forests and a very high risk of forest fires.

"We've arranged fire prevention teams working around the clock to protect the forests," he said.

U Minh Thượng National Park covers over 8,500 ha in U Minh Thuong District. It is the fifth biosphere reserve in Vietnam recognised by UNESCO and the eighth Ramsar site in the country.

The park receives more than 40,000 visitors every year.