At least 15 people were killed and five others were injured in an ambush by militants in southern Thailand's Yala province, according to reports on Wednesday.

The incident happened on Tuesday night; the identities of the militants remain unknown.

Since 2004, the Thai provinces of Pattani, Yala, Narathiwat have been in the grip of a conflict which caused heavy casualties. 

On Wednesday, Thai Prime Minister Prayut Chan-o-cha expressed his condolences to the victims of the incident and said that there is no place for attackers in Thailand and those responsible will face the full force of the Thai law. 

The prime minister, quoted in the media, said that Thailand is a peaceful country and will not tolerate those trying to undermine the sovereignty of the country.

"Let me tell you, these attackers are inhumane," said Prayut, telling the families of the victims: "I will not leave you behind."

The prime minister ordered security and administrative authorities to offer all possible assistance to those affected and to give moral support.