By Kylie Morris BBC correspondent in Bangkok

Buddhists have been targeted in the latest violence

The 60-year-old rubber tapper was found decapitated with a note threatening more killings of innocent Buddhists if more innocent Muslims were arrested.

The violence which persists in the mainly Muslim south is now affecting every level of society.

Talks are scheduled between an Islamic separatist group and the government.

The grisly murder of Sieng Patkaoe marks a turn for the worse in the south. Already, as many as 200 people have died in violence in Thailand's southern provinces since the start of the year.

More than half of them died in one day, on 28 April, when bands of young men launched co-ordinated attacks on security posts.

The government has faced criticism that its response was brutal, with particular concern over the killing of more than 30 alleged militants inside a mosque.

Talks with separatists

Until now, the militants have targeted mainly police or army officers and civil servants. However, farmers are now also fearful of their safety.

A regional police commander say there will be special patrols to accompany rubber tappers into the fields in the early mornings. Similar protection is already provided to schoolteachers.

Talks are scheduled between the leader of a southern separatist group and the government in the coming days.

But the senior army commander in the region has decided not to participate and is reportedly staying in Narathiwat to maintain security.