L'AQUILA, Italy (AFP) - A group of Italian scientists went on trial Tuesday for failing to predict an earthquake that killed more than 300 people in central Italy in 2009 despite signs of increased seismic activity in the area.

The seven defendants -- six scientists and one government official -- are accused of manslaughter in a case that some see as an unfair indictment of science.

Prosecutors say residents around the city of L'Aquila in the mountainous Abruzzo region should have been warned to flee their homes in the days before the quake.

"We simply want justice," L'Aquila prosecutor Alfredo Rossini told reporters.

The injured parties are asking for 50 million euros ($68 million) in damages.

The defendants were members of a panel that had met six days before the quake to assess risks after hundreds of tremors had shaken the medieval university city.

At that meeting, a committee analysed data from the low-magnitude tremors and determined that the activity was not a prelude to a major earthquake.

The only one of the seven defendants present at Tuesday's hearing was Bernardi De Bernardinis, a former senior official in the Civil Protection Agency.

The other defendants include top scientists like Enzo Boschi, the former director of Italy's prestigious National Institute of Geophysics and Vulcanology, as well as Claudio Eva, a physics professor at Genoa University in northern Italy.

"This is a trial which opens on very shaky foundations. You cannot put science on trial," Alfredo Biondi, Eva's lawyer, told AFP. Biondi said his client had told the meeting in question that "one cannot rule out a major earthquake."

The experts are accused of giving overly reassuring information to residents who could have taken adequate protective measures if they had been properly informed.

According to the indictment, the seven are suspected "of having provided an approximative, generic and ineffective assessment of seismic activity risks as well as incomplete, imprecise and contradictory information."

The experts had made it clear that it was not possible to predict whether a stronger quake would occur but had recommended stricter enforcement of anti-seismic measures, particularly regarding building construction.

In an open letter sent to Italian President Giorgio Napolitano, more than 5,000 scientists said the defendants essentially face criminal charges for failing to predict quakes, even though this remains technically impossible.

But Vincenzo Vittorini, a doctor who founded the association "309 martyrs"

and lost his wife and daughter in the disaster, said: "I hope that this trial will change mindsets and will lead to greater attention given to communication on risks."

"No one expected to be told the exact time of the quake. We just wanted to be warned that we were sitting on a bomb," he added

Some 120,000 people were affected by the L'Aquila quake, which also destroyed the city's historic centre and medieval churches.

In the September 14 issue of the science weekly Nature focused on the L'Aquila trial, Thomas Jordan, head of the International Commission on Earthquake Forecasting (ICEF), said the case raises a fundamentally important issue about risk assessment.