Protesters aim to pressure the upper house to select a sympathetic leader in the hopes that it would lead to an appointed government.

Anti-government protesters late Friday marched to Thailand’s parliament as the Senate prepared to elect a new leader after four people were injured when police fired tear gas at demonstrators.

The protesters aimed to pressure the upper house to select a sympathetic leader in the hopes that it would lead to an appointed government. The protest leaders promised to stay overnight near government buildings until the change they want is achieved.

The protesters have been campaigning for the past several months for an appointed government to take over to implement reforms before any further elections take place.

The ruling Pheu Thai Party was projected to win February’s elections, but they were annulled after they were disrupted by protesters.

Friday’s marches took place two days after the demonstrators had won a victory when the Constitutional Court dismissed Prime Minister Yingluck Shinawatra and several members of her Cabinet, ruling that her transfer of a top security official in 2011 in favour of her brother-in-law breached the Constitution.

Tensions have been high in Bangkok since the ruling and as anti-government demonstrators rallied all day Friday, repeating their ambition to “sweep away” Ms. Yingluck’s government. Her party continues to run a caretaker government until new elections are held.

The protesters had already marched to television stations to stop them from broadcasting government-oriented coverage, demanding that the media only broadcast their own messages or non-political content.

Police tear-gassed demonstrators at the government’s Centre for the Administration of Peace and Order, and protest leader Suthep Thuagsuban also led one group of demonstrators to the seat of the Thai government, Government House.

Security forces are also bracing for another set of protest due to begin on Saturday in favour of the government. The pro-government demonstration is to be held north of Bangkok amid fears that the two sides will clash. Mr. Suthep promised to stay at Government House overnight to force the Cabinet to resign.

He called the latest protests the “final fight” and for demonstrators to bring him the new Prime Minister and the Cabinet.

“We can change the government within three days peacefully if we all cooperate together,” he told supporters. “But if within three days we have not gotten rid of [this regime], then we will do what is necessary.”

More In: World | International | News