But the government has refused to carry out the order. The clash, with its fiery street theater, has become a symbol of government inability to resolve one of the worst spates of social unrest in years, and a political test for President Cristina Fernández de Kirchner.

The Villa Lugano encampment is just one of a series of land invasions by thousands of people in the last few weeks that have pushed the capital to the brink of crisis. The ostensible cause, analysts said, is a shortage of low-income housing that has been exacerbated by high inflation and a boom in immigration.

But scratch the surface and there are mind-twisting layers of maneuvering and intrigue that one resident called “Alice in Wonderland” politics, in which the president and the mayor of Buenos Aires are blaming each other.

Aside from the squatters and their neighbors, Mrs. Kirchner, facing an election battle next year, may be in the toughest spot. The land grabs are her first major challenge since her husband, former President Néstor Kirchner, died in October.

Mr. Kirchner was known to play a critical behind-the-scenes role in his wife’s presidency, keeping a lid on social unrest in the poor outskirts of Buenos Aires through his tight-fisted control of unions and local politicians. Argentines, not least Mrs. Kirchner’s political rivals, are watching to see how she responds.

Her first effort did not go well. On Dec. 7, the police tried to oust about 200 squatters from Indoamerican Park, the city’s second-largest park, not far from Villa Lugano. Two people died, reportedly killed by the police, though the police said they used rubber bullets.

The squatters not only refused to leave, but their numbers then swelled to 5,000. Most were Bolivians and Paraguayans, government officials said.

Neighbors protested, saying the foreigners had come to live off the state and take their jobs, and charges of anti-immigrant bias followed.

“This is a country built on foreigners. My grandparents were foreigners,” said Luis Álvarez, 47, who owns a small food market a block from the soccer field in Villa Lugano. “But nobody should get something for nothing. These people arrive in this country and in just a short time they are given all the rights and have no obligations.”

A judge called off the police on Dec. 9 and ordered the government to provide food, water and chemical toilets. The next evening, with no police around, protesters rushed the park with sticks and stones. Guns were fired and a third squatter died.

Residents who led the protest said later that their ranks had been infiltrated by violent soccer hooligans spoiling for a fight.

On Dec. 11 the government sent the military and the police to remove any remaining residents in an orderly fashion, while the city and federal government agreed to create more housing for the poor.

The next day, squatters moved onto the soccer field in Villa Lugano. A judge ordered their “peaceful eviction” on Dec. 13, but Mrs. Kirchner, undoubtedly shaken by the violence at Indoamerican, has yet to comply fully with the order.

She is, analysts say, trapped by her own leftist positions. She often rails against the vicissitudes of “savage capitalism,” has maintained an open-door immigration policy and promoted generous social welfare policies. Tough action against the squatters would not sit well with her political base, but doing nothing does not appear to be an option.

“This is very worrying because before, Néstor Kirchner kept everything under control,” said Carlos Germano, a political analyst here. “Now we are seeing that the government no longer is capable of that. There are dark figures behind the scenes that are at the core of these conflicts.”

The “dark figure” Mrs. Kirchner points to is Mauricio Macri, the center-right mayor of Buenos Aires and a potential rival for the presidency.

Mrs. Kirchner’s national security minister, Nilda Garré, said Thursday that leaders of the soccer field squatters were acting on Mr. Macri’s orders, with the objective of “instilling the idea of a lack of effectiveness in the national government.” She said that one of the organizers, Regino Abel Acevedo, whom a judge issued an arrest warrant for last week, was “Macri’s political broker.”

The mayor has denied the accusations, and says Mrs. Kirchner is refusing to comply with the court order to evict the squatters. Her inaction has emboldened squatters elsewhere, he said, including in nearby Villa Soldati, where some 10 families have been squatting next to a different soccer club for over a month.

“Why can’t she apply the law?” he asked in a television interview last week. “I ask the president to put herself in the shoes of those who live in the community. This situation is absurd.”

The government, meanwhile, has taken other action. Last week, the federal police arrested Guillermo Ramón Ferreira, who they said was the mastermind of the soccer field takeover, and they are searching for three other men. After the Indoamerican Park debacle, Ms. Garré fired the precinct police commander there, and on Friday, she fired the Villa Lugano police chief.

Beyond the political accusations, the intractable conflicts over immigration, housing and the economy at the root of the problem have human consequences.

Mr. Álvarez, the Villa Lugano grocer, worries about a return to the chaos of late 2001, when looters stole or destroyed everything in his supermarket, which he said was 10 times larger than the small market he now operates.

“People can’t take this anymore,” he said. “This whole country is asking for justice and safety, and the government is deaf to the words of the people.”

The squatters, for their part, say rising inflation has made housing unaffordable. Laura Fornos, who is squatting on public land in Villa Soldati with her young son and her mother, said she could no longer pay the rent of $150 a month for a tiny one-room apartment with a shared bathroom. “We don’t want the land; we want a solution, a shack, a house,” Ms. Fornos, 28, said.

But not everything is entirely as it seems. Ms. Garré has told Villa Lugano residents that the squatters are heavily armed. But police officers stationed outside the soccer field there said they did not know if that was true.

Several squatters said that 130 families, about 600 to 700 people, lived in the park, though the police put the total at 90. Most are clearly sleeping somewhere else. While there were about 40 at protest time on Thursday night, on Friday at 7 a.m. the park was nearly deserted, with few signs that people had slept there.

One man, who identified himself only as Luis, 35, explained that most of the squatters sleep in rented apartments in neighboring Ciudad Oculta and return to the park in the afternoons.

“The people here aren’t leaving,” he said next to a makeshift dwelling covered in black plastic. “They are here to stay. We are gathering materials and are about to start building houses.”

*Charles Newbery contributed reporting.