Thirteen schools have been set on fire in southern Thailand, where teachers have increasingly become the targets of a bloody conflict.
More than 200 schools have been torched in the last three years
The Thai authorities have blamed Muslim insurgents for a series of recent attacks on schools, as part of their separatist campaign.
The violence in the region has killed more than 2,200 people since 2004.
More than 200 schools have been torched and 77 teachers killed, according to education officials.
This appears to have been a co-ordinated attack - 13 schools set on fire almost simultaneously on Wednesday evening.
Hours later a bomb exploded in front of another school.
No group has yet claimed responsibility.
On Monday, two female primary school teachers were shot dead in front of their students, and another teacher was killed in an ambush.
In response, hundreds of schools closed their doors this week, with staff demanding better security from the authorities.
Many teachers already carry guns and travel with armed escorts. More than 70 have been killed in the past three years.
Muslim separatists are accused of targeting schools and Buddhist monks because they are seen as symbols of the state.
The violence appears to have escalated in recent months, with almost daily attacks taking place in Thailand's three southernmost provinces.
In a separate incident, a man was reportedly gunned down late on Wednesday in a drive-by shooting in Yala province.