By Isla Binnie

ROME (Reuters) - Italy has committed human rights abuses that may amount to torture as it tries to process tens of thousands of boat migrants, Amnesty International said on Thursday, prompting a sharp denial from the national police chief.

The report included allegations of beatings, electric shocks and sexual humiliation in a handful of cases involving mainly African migrants who resisted having their fingerprints taken.

Italian police chief Franco Gabrielli dismissed the accusations, saying his officers, who work alongside EU officials and human rights groups in the migration centers, had shown enormous responsibility in dealing with the crisis.

"I categorically deny that violent methods are used on migrants both during identification and during repatriation," Gabrielli said in a statement.

Italy has become the main arrival point in Europe for people fleeing persecution and poverty in Africa, most of them crossing the Mediterranean from lawless Libya in search of a better life.

Unnerved by migrants surging through Italy into northern Europe, the European Union called in September 2015 for Italy and fellow frontier state Greece to set up "hotspots" to identify and fingerprint the migrants.

European law says migrants must stay in the country where they first enter the bloc, and that is determined by where they give their fingerprints. Until last year, most migrants refused to be identified and headed straight for the richer north.

"In their determination to reduce the onward movement of refugees and migrants to other member states, EU leaders have driven the Italian authorities to the limits, and beyond, of what is legal," Amnesty researcher Matteo de Bellis said in a statement.

The European Commission said the hotspots were legal and respected fundamental rights, adding that EU agencies and aid groups on the ground in Italy had not reported any wrongdoing.

"Any form of violence or abuse of rights of refugees is unacceptable and we take any allegation seriously. We will be liaising with the Italian authorities to ensure that none of these claims are founded," a Commission spokeswoman said.

ALLEGATIONS OF ILL-TREATMENT

Amnesty said it had interviewed more than 170 refugees and migrants in Italy since July 2015. Most had not refused to give their fingerprints and reported no problems, but 24 people alleged having been subjected to ill-treatment by police.

Several others said unnecessary or excessive force had been used to make them give their fingerprints, Amnesty added.

Amnesty quoted a man named only as Adam, a 27-year-old from Darfur, Sudan, saying police beat and subjected him to electric shocks with a stun baton before making him take off his clothes and pulling on his testicles with pliers.

The report said such treatment amounted to torture within the United Nations Convention Against Torture. It also said some people were detained arbitrarily.

It also condemned the assessment process for arrivals in the hotspots, which is aimed at selecting asylum seekers from those considered irregular migrants.

"People, often exhausted and traumatized from their journeys and without access to adequate information or advice on asylum procedures, have to answer questions with potentially profound implications for their futures," it said.

Over the past three years more than 470,000 migrants, mainly from sub-Saharan Africa, have reached Italy by boat. At least 3,750 have died this year alone while making the crossing.

(Reporting by Isla Binnie, additional reporting by Robert-Jan Bartunek in Brussels; Editing by Crispian Balmer and Gareth Jones)