Hundreds of Thai monks have led nine elephants in a march on parliament calling for Buddhism to be enshrined as the country's official religion
They were joined by more than 1,000 supporters who also want Buddhism to be declared the national religion in the new post-coup constitution.
The leaders behind last September's coup have indicated they may be willing to bow to the monks' demands.
Critics fear it could inflame tensions in the Muslim-majority deep south.
In the south a three-year Islamic insurgency - in a country where 95% of the population are Buddhist - has killed more than 2,000 people.
Correspondents described a colourful procession as monks dressed in saffron-robes walked alongside the nine elephants 30km (18 miles) from Bangkok's western suburbs to parliament.
Police had asked the protesters not to bring the elephants for fear the scorching heat would make them difficult to control, but they relented as the march continued into the city.
"Our only demand is to have the clause 'Buddhism is Thailand's national religion' included in the new constitution. It's the opinion of the majority of Thais," protest spokesman Tongkhao Phuangrodpang told the AFP news agency.
Thai monks march with elephants calling for Buddhism be made the national religion