United Kingdom's authorities have arrested an Egyptian man who is believed to be the mastermind behind the smuggling of thousands of people across the Mediterranean from Libya and the rest of North Africa into Italy.

The 40-year-old Egyptian national, who was detained in Hounslow, West London, on Wednesday, had been under questioning on suspicion of facilitating illegal immigration, Organized Crime and Corruption Reporting Project (OCCRP) said.

It added that the National Crime Agency investigators suspected that the man was working with people smuggling networks in North Africa to organize boats that could carry hundreds of migrants at a time. He was also believed to have maintained communication with criminal associates during the crossings. He was also linked to a number of illegal crossings from North Africa to Italy over the past year.

The National Crime Agency's senior investigator Darren Barr said they "suspect this man has been running his operation from the UK, and masterminding the smuggling of thousands of migrants. The type of boats organized crime groups use for crossings are death traps, and sadly many people have died after incidents in the Mediterranean, which demonstrates the level of danger."

A boat carrying at least 800 immigration who set off from the coast of Tobruk in eastern Libya to Italy capsized off Greece. The Greek Coast Guard managed to rescue only 104 people.