Brazil's first elected leftist president, Luiz Inacio Lula da Silva, came to office 15 months ago with promises to redistribute property. But leaders of urban and rural squatter groups say his administration's efforts have fallen short.
Police arrested nine people and said four suffered minor injuries after officers flushed out the squatters who broke into the building in Sao Paulo's center before dawn.
Hundreds more took over a large plot of vacant land on the city's outskirts and started setting up makeshift shacks, authorities said. Officers managed to prevent hundreds more squatters from taking over five more vacant buildings, said Saulo de Abreu, Sao Paulo state's security chief.
The Sao Paulo sit-in was the first urban protest this year after nearly a month of land seizures in rural areas by landless peasants.
Silva, speaking out about the protests for the first time, said Monday his government is trying to grant 130,000 titles to people squatting on unused land across the country.
Silva, the country's first working class president, said Brazil's landless are free to protest, but said the seizures could hurt the reform efforts that have been opposed by business groups, ranchers and centrist politicians.
``People should not lose their sense of responsibility,'' Silva said on his radio show. ``People should realize that acting radically does not help us.''
Land ownership among Brazil's rural and urban poor is one of the starkest signs of inequality in a country where more than 40 million people earn less than $1 a day.
About 90 percent of the land is owned by just 20 percent of the country's 178 million people. The poorest 40 percent of the population hold just 1 percent.
``These occupations wouldn't be necessary if the government did more to help us find places to live,'' said Roque Cuello, who is helping oversee the squatters setting up camp Monday on a vacant lot owned by Sao Paulo's state government
The urban property invasion attempts are the first since last July, when thousands of squatters took over four large, unused apartment buildings and a huge lot owned by Volkswagen in front of one of the carmaker's biggest Brazilian plants.
In the last month alone, the Landless Rural Workers Movement says it has moved nearly 100,000 people onto rural land it claims is not being used in attempts to gain title to the properties.
The highest concentration of rural seizures have been in the destitute northeastern state of Pernambuco, where Silva was born and grew up.