Brazilian authorities say two people have been shot dead in a confrontation involving landless peasants at a Swiss-owned farm in the southern state of Parana.

Officials said Monday that a peasant leader and a security guard were killed after the farm owned by the Syngenta company was occupied by activists from Brazil's Landless Rural Workers Movement and the peasant rights group, Via Campesina.

The demonstrators had invaded the farm to protest its use of genetically modified seeds. At least three guards and three activists also were reported injured.

Local officials say the confrontation also involved armed men who had shown up to retake the property from the activists. Syngenta says its contract with its security company requires its guards to be unarmed.

Last year, protesters camped out at the farm, alleging the company is illegally experimenting with research into genetically modified crops. The company denied breaking any laws.

The Landless Workers Movement has occupied numerous farms over the years to pressure the Brazilian government into speeding up the expropriation of unproductive land.

Some information for this report was provided by AP and Reuters.