Two Thai high school student leaders will be charged for joining a banned protest last month, police said yesterday, a day after embattled Prime Minister Prayuth Chan-ocha threatened tougher action against protesters. 

The students said they had been summoned for violating an emergency decree by joining a protest on Oct 15, when tens of thousands of people defied a ban by Prayuth aimed at halting protests demanding his removal and reforms of the monarchy.

"Even if you arrest protest leaders, there is not enough space in prison because hundreds more will rise up," one of the students, 15-year Benjamaporn Nivas, told Reuters in an instant message.

Youth- and student-led protests since July have become the greatest challenge to Thailand's establishment in years and dozens of arrests and attempts to quell them have so far only brought more people into the streets.

Prayuth has refused the protesters' demand to resign. Protesters also seek to redraw the constitution written by his former junta and curb the powers of King Maha Vajiralongkorn, saying the monarchy has enabled decades of military domination.