Several injured as violent clashes erupt in Bangkok
According to details, the demonstrators were trying to reach Parliament House area when police attempted to stop them resulting in clashes between both.
Protestors hurled smoke bombs and bags of paint at police, who retaliated with tear-gas.
The parliament at that time was debating possible changes to the constitution. Although the proposed constitutional changes have been one of the major demands of protestors, they were worried that lawmakers would dismiss most of their demands - in particular, the one calling for reform of the monarchy.
The reforms proposed by demonstrators include holding Thailand's King Maha Vajiralongkorn more accountable and also reform the senate, where the members are unelected.
The student-led anti-government movement has become the greatest challenge to Thailand's ruling establishment with escalated demonstrations over the past three months.
The protestors are demanding the resignation of Mr Prayuth, who is a former army chief and seized power in a 2014 coup before becoming premier last year after a controversial election.