Members of a landless peasant group, some wielding sticks or knives, attacked a cellulose factory in a violent protest against its use of genetically engineered eucalyptus plans, video released by organizers showed.

The MST landless movement said about 1,000 women took part in the protest Thursday at the Suzano/Futura Gene site at Itapetininga, some 170 kilometers (115 miles) from Sao Paulo.

A video posted by the group showed masked women smashing greenhouse panes and destroying plants at the site, while others painted slogans alleging that "genetically modified plants destroy biodiversity."

Some of the women in the video were armed with knives or sticks.

The action was part of wider protests against Suzano/Futura Gene, a pulp and paper producer, as it seeks to win government approval for the genetically modified plants.

Around 300 supporters of the Via Campesina rural protest movement meanwhile interrupted a meeting of Brazil's Technical Commission on Biosafety (CTNBio), which regulates genetically modified plants, in the capital Brasilia, where Suzano/Futura Gene was presenting the new modified species.

The CNTBio discussions are due to resume in April after the protest disrupted FuturaGene's attempt to obtain of industrial GE plantation.

Atiliana Brunetto, representing the landless legalization movement, said that even if the genetically modified eucalyptus plant could boast 20 percent higher productivity than the traditional version it would require greater use of pesticides and water to cultivate, thereby harming the environment.

"The most important thing is we have managed to bring the debate into the public domain," Brunetto said.

Suzano/Futura Gene said it deplored the destruction of plants, the result of 14 years of studies.

The landless women face charges of damaging private property.