Authorities reported Wednesday that at least four people had died in landslides in Krabi province, bringing to 15 the death toll in the flood-battered region. More than 100 people were injured, and dozens missing.

With access to some of the seven villages hit by landslides difficult and much of the region’s telephone service cut off, it was feared the actual death toll was higher.

Vittayen Muttamara, deputy director of the government’s flood center, said 716,110 people have been affected by floods from nearly a week of heavy rain in eight southern provinces. Many urban and rural areas were inundated, and connecting roads blocked by mud and rock slides.

The Thai navy dispatched three vessels to help evacuate tourists from resort islands such as Koh Samui, to which air service was intermittent because of flooding around its airport. Private ferry operators also pitched in.

Prime Minister Abhisit Vejjajiva visited the region Wednesday morning and ordered residents evacuated from all areas at risk.

"If you ask people who are familiar (with the situation), they would tell you they never expected this could happen," he said. "We cannot use the past experience as a guideline because many things have changed. Therefore, I’d like everyone to think of safety first in the risky areas and we will facilitate the evacuation in the necessary areas."

Thailand’s weather bureau said torrential rains were expected for one or two more days over much of southern Thailand. It warned of more flooding and wind-whipped waves making sailing unsafe for small boats.