BRASILIA, Brazil: Brazilian police fired rubber bullets and tear gas Wednesday at a 15,000-strong landless protest in the capital Brasilia, injuring two, a spokesman for the demonstrators said.
The spokesman told AFP police moved in after marchers carried material from a bus to erect a barricade.
"When the police saw us taking the material out of the bus they rushed at us with gas, with everything," he said.
The march began peacefully but protesters clashed with police as they neared the presidential palace.
President Dilma Rousseff was not in the building.
The protests were only the latest in a series which have hit Brazil in recent weeks, heightening tension just four months before the country hosts the World Cup.
A protest in Rio de Janeiro ended in tragedy last Thursday when a TV cameraman was killed after he was struck on the head by a flare thrown by a demonstrator.
This year has seen sporadic protests in Brazil.
Last week's unrest in Rio was sparked by the latest rise in transport fares, the issue which prompted nationwide demonstrations last June.
Brazilians are angry at poor public services while their country spends billions of dollars to host the World Cup and the Rio Olympics in 2016.
Wednesday's marchers in Brasilia comprised agricultural workers who were marking 30 years of the landless movement MST.
Across the square from the protest Brazil's Supreme Court suspended its session owing to the size of the protest.
"There was no attempt to enter the court building but security advised the session be suspended given the number of protesters," a spokesman told AFP.
After the clash with police the marchers began to disperse and head for Brazil's nearby Congress building.
The landless workers movement has spent decades demanding successive governments undertake wide-ranging land reform and are frustrated at the slow progress being made.