Seven Italian scientists have been sentenced to six years each in jail for reassuring the population they were safe from a major earthquake, just days before the deadly 2009 tremor in L'Aquila.

The single judge at the L'Aquila regional court, Marco Billi, found the seven guilty of multiple manslaughter and bodily harm in relation to the 6.3 magnitude quake that shattered the central Italian town and killed 309.

"I consider myself innocent in front of God and men," defendant Bernardo de Bernardinis told reporters after the sentence was read.

"I feel depressed and in despair," said Enzo Boschi, the former chairman of the Italian Institute of Geology and Volcanology, "I thought I was going to be acquitted. The sentence is mind-boggling and nonsensical. I still have no clue of what I am accused of."

Six days before the quake on 6 April, 2009, the seven defendants - all members of the National Commission for the Forecast and Prevention of Major Risks - signed a report saying a major disaster was unlikely because only minor tremors had been reported over the previous week.

But prosecuting lawyers told the court that the information in the report was "inexact, incomplete and contradictory" and that the scientists made an "approximate evaluation of the risks" involved.

Their reassurances "led [the earthquake's] victims to stay in their houses," which collapsed when the quake structk, the prosecution said.

The defence maintained that science has not developed a way to predict major earthquakes.

In the closing statement prosecutors said the trial was brought because Guido Fioravanti, the son of two victims, said his parents died because they trusted the state.

"On other occasions they would have fled but that night they told themselves what the Risk Commission had said. And they stayed," Fioravanti said.

It took about four hours for Billi to reach a verdict. Prosecutors had asked for a four-year sentence only but the judge convicted the defendants to six years each and ordered costs and damages of €7.8m (£6.4m).

The scientific community has rallied to the defence of the defendants. Science, itself, had been put on trial, they argued.

More than 5,000 scientists wrote an open letter to Italian president Giorgio Napolitano to protest against the "unfair and naïve" prosecution.