BANGKOK -- The number of Myanmar refugees killed in a fire at a camp in northwestern Thailand has risen to 35, Thai officials said Saturday.

The public health chief of Mae Hong Son province, Paisarn Thanyavanichkul, said police and rescue workers found 35 bodies after Friday's fire at the Ban Mae Surin refugee camp. He said Saturday that another five people were seriously injured and 20 to 30 others slightly injured. One refugee was missing.

Hundreds of thatched huts in two camp sector burned to the ground before the fire was put out Friday evening, leaving about 2,300 refugees homeless, the UN High Commissioner for Refugees said in a statement issued Saturday. UNHCR said the camp's clinic and food distribution center were also destroyed in the fire.

Authorities are investigating the cause of the fire, but initial reports suggest the blaze was sparked by a cooking accident.

"We are deeply saddened by this tragic incident and doing what we can to provide instant relief," said UNHCR's Representative in Thailand, Mireille Girard. "Our teams are returning to the camp this morning with plastic sheets, blankets, bed mats and other items to provide temporary emergency shelter before their homes can be rebuilt."

The Thai government as well as relief organizations such as the International Rescue Committee and International Committee of the Red Cross were offering support for those impacted by the fire.

About 3,300 refugees, mostly from Myanmar's Karen minority, live at the Ban Mae Surin camp, which was set up in 1992 and is located in rough terrain 90 kilometers (55 miles) from Mae Hong Son town. More than 100,000 refugees live in Thai camps near the Myanmar border, mostly ethnic Karen who fled fighting between Karen guerrillas and the government.