Thai police used water cannon and rubber bullets to disperse the crowd gathered near the King's Palace in Bangkok on Saturday. At least 11 people were hurt during the clashes, the city's Erawan Emergency Medical Centre said.

More than 1,000 demonstrators had gathered to demand the release of protest leaders, whose mass trial on charges of sedition and insulting the monarchy began this week.

"The police officers will remain in the area until peace and order has truly been restored," police spokesperson Krissana Pattanacharoen said.

At least five protesters have been arrested. 

How did the protest turn violent?

The rally was mostly peaceful, although some protesters threw firecrackers and allegedly used slingshots to fire objects at the police, authorities said.

The organizers also said they planned to fly paper planes with messages over the palace walls. However, tensions escalated when protesters broke through a barricade of shipping containers. The police police erected the wall, which was two-container tall, on a historic field in front of the palace to keep the marchers from getting close to the palace.

Hundreds of police in riot gear and shields advanced to push people away from the palace area.

Once protesters were able to get through, they threw Molotov cocktails at police who retaliated with water cannon jets and rubber bullets.

Why have protesters returned to the streets?

The fresh protests also took place after parliament this week failed to pass a bill to rewrite the military-backed constitution, one of the protesters' main demands.

The protest movement is also calling for the reform of the monarchy — including the abolition of draconian royal defamation laws.

The laws shield the ultra-powerful King Maha Vajiralongkorn and his family from libel, but rights groups say their broad use means anything perceived as criticism can land a person in jail for up to 15 years per charge.

Since the movement kicked off in July, with thousands of students taking part, more than 60 people have been charged under the lese majeste law.

"We're demanding real democracy and not a government that says it is elected but comes from the army,” said a man who gave his name as Kung. "The world has changed and we want the same kind of monarchy as in Western countries.”

The youth movement has posed the biggest challenge so far to Prime Minister Prayuth Chan-ocha, who critics say has manipulated the law to keep himself in power in the years following the 2014 military coup.

mm/dj (AFP, dpa, Reuters)