Thousands of anti-government Thai protesters marched to an army barracks on Sunday to challenge King Maha Vajiralongkorn's personal control over some army units.

It was the latest act of defiance against the king by protesters who have broken taboos by criticising the monarchy. The Thai constitution says the monarchy must be revered and laws ban insulting the institution.

Protesters, many carrying inflatable ducks which have become a protest mascot, stopped at the gates of the 11th Infantry Regiment, part of the King's Guard that played a role in the suppression of anti-establishment protests in 2010.