Italy on Saturday commemorated the fourth anniversary of a devastating earthquake in and around the city of L'Aquila which killed 309 people and forced tens of thousands to abandon their homes.

Families of the victims led a torch-lit procession with thousands of people in the night between Friday and Saturday, when the tremor struck the mediaeval university town in the middle of the Apennine mountains in central Italy four years ago.

Reconstruction efforts have been heavily delayed -- largely due to red tape and a lack of funds -- and much of the city centre still lies abandoned.

Local archbishop Giuseppe Molinari celebrated mass in the night in a church in L'Aquila that was heavily damaged. A church bell rang out 309 times at 3:32 am (0132 GMT) -- the exact moment that the 6.3-magnitude earthquake struck.

"Everything has been delayed. And young people are leaving. Politicians keep bickering," Molinari told Catholic news site tempi.it, adding: "We would like to see something move so we can start again. The situation is still critical."

Italian Senate speaker Pietro Grasso on Saturday laid a wreath at a student dormitory that collapsed four years ago, killing eight people.

Territorial Cohesion Minister Fabrizio Barca, who has promised to speed up the reconstruction, said: "The state cannot not rebuild this city."

A court in L'Aquila last year sentenced six scientists and a government official to six years in jail for multiple manslaughter for failing to provide sufficient warning to local residents following a wave of small tremors.

The seven defendants are appealing the sentence.