"Some of them sought to escape by breaking through a gate, but they were pushed back by security forces.
"A fire broke out in one of the buildings housing the illegal immigrants, largely destroying it."
A preliminary report found some 40 immigrants were injured in the incidents, said Laura Boldrini, a spokeswoman for the UN High Commissioner for Refugees (UNHCR) in Italy.
Six of the immigrants were hospitalised, according to the ANSA news agency, which also said 27 security officers were injured.
The fire was brought under control and order restored, police said.
About 20 immigrants have been arrested over the fire, which they allegedly started to protest against the announced repatriation of 107 Tunisian illegal migrants, ANSA said.
The islands off southern Italy, especially Lampedusa, have seen a flood of illegal immigrants mainly from northern Africa reach their shores in a bid to enter Europe.
In January the Italian government began a system to speed up the repatriation of the illegal arrivals which has raised tensions in the holding centre.
On January 24, some 700 immigrants forced down the gates at the centre and marched in protest through the streets of Lampedusa for several hours.
"These new measures have shattered the calm which existed at the holding centre, which had become a model for the responsible management of the influx of immigrants. The work by HCR and other organisations has gone up in smoke," said the UNHCR spokeswoman.
Some 31,700 immigrants landed on Lampedusa in 2008, a 75 percent increase from the previous year, according to official figures.
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