BANGKOK (REUTERS, BLOOMBERG) - Thailand's King Maha Vajiralongkorn said "the country needs people who love the country and love the monarchy", in pre-recorded comments broadcast on state television on Friday (Oct 16) from an event a day earlier.

The King has made no direct comment on three months of protests that have called for curbs to his powers as well as for the removal of Prime Minister Prayut Chan-o-cha, a former military ruler.

The King was addressing a group of ex-communists in northern Thailand.

"All your experience and the things that you've done. You can teach the new generation of your experience. This will be greatly useful," he told them.

The comments were aired as thousands of anti-government protesters gathered in the Thai capital for a third straight day after Mr Prayut rejected calls to quit, escalating a three-month-old movement demanding greater democracy and less power for the monarchy.

Riot police used water cannons to try and disperse demonstrators, who defied emergency rules and a ban on large gatherings with a last-minute change in the protest venue to hold rally at the main intersection near the MBK Center shopping mall in central Bangkok.

A flash mob also staged a rally in Chiang Rai province in northern Thailand as protest leaders called for demonstrations across the nation.

Protesters are calling for monarchy reform as well as a rewriting of the Constitution, which was drafted by a military-appointed panel after Mr Prayut took power in a 2014 coup.

The charter was instrumental in helping Mr Prayut retain power after 2019 elections.

Mr Prayut on Friday said he will not resign, and the emergency rules that he declared on Thursday will be in place for 30 days, or less if the situation improves.

The state of emergency for Bangkok was announced after tens of thousands of protesters broke through police lines and surrounded Mr Prayut's office on Wednesday night.

The protesters' use of social media to plan their gatherings and open defiance of police point to the resolve of the movement's leaders to keep up the pressure until their demands are met.

The movement, led at first mostly by students, has broken taboos about publicly criticising the royal family, which sits at the apex of power in Thailand.

Police have said legal actions will be taken against those who violated the ban on gathering of five or more people.

On Friday, the protesters called for the release of arrested activists and urged people to join the rally to strengthen the movement.