At least 17 girls were killed in a school dormitory fire in Thailand, according to police.

The fire is said to have happened at a Christian school in the north of the country in Chiang Rai, where girls between three and 13 attend.

"The fire broke out at 11pm on Sunday; seventeen girls were killed and two are still missing, with five injured", a police colonel told AFP.

"Most of the losses were because the children were asleep.

"Those that got out were awake".

Two of the injured girls are in critical conditions. Police are investigating the cause of the blaze.

The damage inside the dormitory Credit: AP