Security personnel remove a shelter where Cambodian National Rescue Party leaders give a speech to their supporters at Democracy Square in Phnom Penh, Cambodia, Saturday. Pic: AP.

PHNOM PENH, Cambodia (AP) — Cambodian police on Saturday dispersed about 1,000 anti-government demonstrators from a park in the capital, Phnom Penh, a day after four people were killed in a crackdown on a labor protest.

Hundreds of anti-riot police moved in after warning the protesters to leave the area known as Freedom Park, where they have camped since mid-December to demand that Prime Minister Hun Sen step down and call new elections. They claim that a July vote was rigged and the opposition Cambodia National Rescue Party robbed of victory.

At least four people were killed Friday when police opened fire to break up a protest by striking garment workers demanding a doubling of the minimum wage.

The latest crackdowns indicate a hardening of the government’s response to opposition and labor protests, which have been generally peaceful since the elections.

One measure of the seriousness of the situation was an unusual statement issued by the Defense Ministry after Friday’s deaths, affirming the military’s loyalty to the government. The statement said the army would take whatever action was necessary to defend the government, the king and the constitution. It said that the armed forces regretted learning that some opportunists and politicians insulted the government and incited people to oppose Hun Sen’s leadership by bringing about instability.

Rumors were rife in Phnom Penh on Saturday that arrest warrants were issued for opposition and labor leaders, though officials denied that was the case.

The park — a venue for political demonstrations — was cleared after Phnom Penh Gov. Pa Socheatvong sent a letter to opposition leader Sam Rainsy banning the use of the park this and next weekend, as well as marches through the city’s streets, citing security reasons. The letter said the ban would be lifted once the situation improved.

Major rallies are held at the park on weekends, and the turnout was expected to be larger than usual this time because of anger at Friday’s fatal confrontations with workers.

While police who cleared Freedom Park were not visibly armed, they acted forcefully and were joined by unidentified plainclothes men carrying iron pipes, who milled around the area afterward in an effort to discourage the protesters from regrouping.

Lang Rith, a 29-year-old demonstrator from southern Takeo province, said he was hit with baton on his back as he tried to run away from the park.

“They beat us like they beat animals. I am very scared,” Lang Rith said.

The opposition party CNRP issued a statement calling on its followers to maintain a policy of non-violence and appealed to civil society groups and foreign embassies to serve as witnesses to government violence.

The local human rights group LICADHO earlier said in a statement that at least four civilians were shot dead and 21 injured Friday in what it described as “the worst state violence against civilians to hit Cambodia in 15 years.”

“The use of live ammunition was prolonged and no efforts appear to have been made to prevent death and serious injury,” it said. “Reports suggest that security forces were also injured after being hit with stones.”

The U.N. special rapporteur on human rights in Cambodia, Surya Subedi, said Friday’s incident was the third time since the disputed elections that authorities have shot into a crowd and caused fatalities. He called for an independent investigation into whether excessive force was used. He also expressed concerned about increasing violence by some demonstrators.

The United States said it deeply regrets the loss of life in the violent clashes between protesters and government security forces. The State Department said that the U.S. Embassy in Phnom Penh has been in contact with representatives from all sides to urge the exercise of maximum restraint and respect for the rule of law.

The standoff over wages presents Hun Sen with a dilemma, as increasing violence could drive the workers into a tighter alliance with the opposition, providing a vast pool of people for their increasingly confident street demonstrations. But the government is also close to the factory owners, whose exports fuel the economy and who are generally seen as financial supporters of Hun Sen’s ruling Cambodian People’s Party.