Thailand was set for an earlier than expected election after its king endorsed Prime Minister Anutin Charnvirakul's bid to dissolve parliament on Friday, as a border conflict with Cambodia raged and the government moved to head off a no-confidence vote.

Anutin's move comes as the military conflict between Thailand and Cambodia entered its fifth day, with at least 20 killed, more than 260 wounded and hundreds of thousands displaced.

Since then Thailand has carried out air raids in Cambodia, which responded with rocket fire.