PARIS - Around 100 environmental activists entered a factory belonging to US biotech giant Monsanto in southwest France on Friday aiming to destroy any genetically modified (GMO) seeds, officials said.

The protest ended after a few hours with no damage caused. It came a day after Monsanto vowed to press on with GMO tests despite France's top court cancelling two field trial licences, saying it had not given enough information on their location.

The activists, members of environmental group Greenpeace, farm union Confederation Paysanne and anti-GMO group Faucheurs Volontaires, said they wanted to destroy Monsanto's GMO maize seeds which were due to be sown in the coming weeks.

"We know Monsanto produces genetically modified seeds that are likely to be sown this year. We wanted to find them and make them unusable," Arnaud Apoteker, head of Greenpeace's anti-GMO division, told Reuters. He said no GMO seeds had been found.

Monsanto is one of several biotech companies producing GMO maize (corn) seeds that will be sown on around 5,000 hectares of French land for commercial sale this season, 10 times the area sown in 2005. The company also intends to hold GMO experiments on 17 sites around France this summer.

"It's absolutely shameful and unacceptable" a Monsanto spokesman told Reuters.

France is home to a large and vocal anti-GMO lobby and around half of all GMO test fields are destroyed each year.

"In the long run we wonder whether these unacceptable actions will not call into question agricultural innovation in France, a famous world agricultural power," Monsanto said in a statement. (Additional reporting by Paule Bonjean)