Italian prosecutors are investigating whether the wrong man was extradited to Italy on charges of controlling a migrant trafficking network after reports suggested it may be a mistaken identity case.

Eritrean Medhanie Yehdego Mered, 35, dubbed "the general" and described as "cynical and unscrupulous", is accused of shipping thousands of people to Europe and sending some to a watery grave.

Italian police announced Wednesday that Mered, arrested in Sudan with the help of Britain's National Crime Agency, had been extradited to Italy, releasing video and photograph images of him being brought off a plane in Rome.

But Palermo prosecutor Francesco Lo Voi was forced to admit Thursday his team was "carrying out the necessary checks" after the BBC spoke to friends and family of the arrested man who said it was a case of mistaken identity.

AFP also interviewed people in Sudan who said the detainee was not Medhanie Yehdego Mered.

"The identification of the suspect, his arrest, his handing over and his extradition to Italy were communicated to us in an official manner by the NCA and the Sudanese authorities through Interpol," Italian media quoted Lo Voi as saying.

An NCA spokeswoman said "we're aware of the media reports. It's a bit too soon to speculate at the moment".

Friends of the arrested man told AFP his name was Mered Tesfamariam, and he was a 27-year-old migrant.

"I know this man since he arrived in Sudan in 2014, his name is Mered Tesfamariam. The person who has been taken to Rome is not the general. The man taken to Rome doesn't even speak Arabic," Eritrean Tasfie Haggose, 38, said in Khartoum.

Secret mover

"The general is well known among Eritreans, especially among those who have tried to cross the Mediterranean. The general moves secretly. He does not deal directly with people who want to migrate. He deals through mediators or brokers," he said.

Fellow Eritrean Barhi Kobron, 28, said he too knew the detainee.

"This man used to move freely among people, which is not how the general behaves. The general has no house in Khartoum. He moves between Sudan, Ethiopia, Libya, and between Khartoum and eastern Sudan."

Medhanie Yehdego Mered, on a wanted list since 2015 for people smuggling, is accused of packing migrants onto a boat that sank in 2013 off the island of Lampedusa, claiming at least 360 lives in one of the worst disasters in the Mediterranean.

Referred to in wiretapped conversations between his subordinate alleged traffickers as "the general", Mered is accused of organising the smuggling of up to 8,000 people a year on migrant boats.

Italy, Sudan and Britain had hailed his capture as a significant blow to the people smuggling business as Europe moves to stem the flow of migrants across the Mediterranean.

According to the UN's refugee agency (UNHCR), over 48,500 people have arrived in Italy by boat so far this year.

More than 10,000 people have died crossing the Mediterranean to Europe since 2014.