BANGKOK, Thailand -- Supporters of Thailand's embattled government on Saturday warned the country's judiciary and Senate against any attempt to install an unelected prime minister, saying it would be a disaster for the nation that could spark civil war.

Jatuporn Prompan, who heads the pro-government Red Shirt movement, made the comment to reporters during a rally on the western edge of Bangkok that was held three days after Prime Minister Yingluck Shinawatra was ousted in a controversial ruling by the constitutional Court.

The ruling emboldened anti-government protesters, who on Friday ramped up their efforts to bring down what remains of Yingluck's administration by laying siege to television stations, surrounding state offices and demanding lawmakers help them install a non-elected prime minister to rule the country.

Yingluck's Cabinet has named deputy premier Niwattumrong Boonsongpaisan as acting prime minister, but the leader of the anti-government protest movement, Suthep Thaugsuban, said Saturday that Niwattumrong "doesn't hold the authority and status to be the head of the government."

Suthep said the Senate should "quickly consult the presidents of the Supreme Court, the constitutional Court, the Supreme Administrative Court and the Election Commission to work to appoint the new prime minister immediately."

The anti-government protesters called Friday for a "final push" to oust the entire Cabinet and set up an unelected "people's council" that they say would implement still-undefined reforms to combat corruption and fight money politics. They oppose elections scheduled for July, which the current ruling party would likely win.

Jatuporn, however, insisted that the current government was legitimate and denied there was any political vacuum in the wake of Yingluck's departure. There is only "the political vacuum that the elites, including Suthep, are attempting to create," he said Saturday.

Appointing an unelected prime minister "will inflict a crisis on the nation, because the only solution for Thailand is democracy under the king as head of the state," Jatuporn said.

"I want my voice to be heard by the presidents of three courts and the Senate ... that you are going to create a disaster in the nation," he said. "You are going to create a serious crisis that could lead to a civil war that no one wants to see."

Thailand's long-running political crisis began in 2006 when Yingluck's brother, former Prime Minister Thaksin Shinawatra, was toppled by a military coup after being accused of corruption, abuse of power and disrespect for King Bhumibol Adulyadej.

Thaksin, a former telecommunications billionaire, remains highly popular among the rural poor in Thailand's north and northeast, and parties controlled by him have won every national election since 2001. The anti-government protesters, aligned with the opposition Democrat Party, say they want to remove all traces of his political machine from politics.

The protesters achieved a partial victory Wednesday when the constitutional Court ousted Yingluck, saying she had violated the constitution by transferring a senior civil servant to benefit her politically powerful family. Nine other Cabinet members were also forced from their posts.

Analysts said the ruling was another blow to Thailand's fragile democracy, and that it added to a growing sense that the nation's judiciary is biased in favour of a powerful conservative establishment of elites backed by royalists and the army.

With anti-government protesters on the streets of Bangkok and the Red Shirts rallying on the city's western edge, there have been concerns about violence. Jatuporn said "each side should take care of their own supporters" and avoid confrontation.

Since the latest political crisis intensified in November, 25 people have died in protest-related violence and more than 800 have been wounded.

On Friday, police fired tear gas and water cannons to push back hundreds of anti-government demonstrators who attempted to force their way into the government's security agency. Six people were injured.