By Steve Kingstone
BBC correspondent in Sao Paulo
There has been a sharp increase in the number of illegal farm seizures by landless peasants in Brazil.
Landless Brazilians are impatient with the pace of change
Across the country, more than 50 properties have been invaded since mid-March by rural people who want the government to speed up land reform.
The governing Workers Party has traditionally been seen as an ally of the agrarian Movement, or MST.
President Luiz Inacio Lula da Silva, who has vowed to help the landless, now finds himself in an awkward position.
He has announced plans to resettle more than 100,000 landless families this year - but the MST says the pace of resettlement is too slow.
The land issue is as old as Brazil itself.
When the Portuguese first settled here, vast estates were shared out between a small number of aristocrats.
Five-hundred years later, nearly half of all farmland is still owned by just 1% of the population.
Lula wants to help the landless without frightening investors
Formed in the 1980s, the MST tries to force change by seizing disused farmland and occupying high-profile buildings, such as banks and local government offices.
In March there were 40 such invasions - the highest number in a single month for five years - and the pattern has continued into April.
Over the Easter weekend two farms have been occupied in the state of Sao Paulo.
In the words of the MST leader, the aim is to "raise hell" and put pressure on the president.
It is a tricky issue for him. If he gives in to the MST he will be accused of rewarding illegal occupations.
If he does nothing, he will unnerve international investors.
A foreign-owned tree plantation was among the properties briefly occupied last week.
For now, the president is striking a balance, making available additional land in 11 states and promising an extra $500m towards agrarian reform over the next two years.
But at the same time, he has warned the MST that the government will cut off dialogue if the group continues to occupy working farms and public buildings.