German police have conducted major raids on a group of suspected people smugglers, according to reports.

Around 400 officers, among them federal police and GSG 9 special units, searched more than 20 apartments and offices, mainly in Berlin, but also in the eastern state of Saxony-Anhalt, the dpa news agency said.

Five men were reportedly arrested, four of them in Berlin and one in the city of Halle, while another 12 suspects are under investigation.

The group is said to have brought at least 90 people, mostly from Turkey and Iraq, to Germany, with each paying several thousand euro.

They were flown from Istanbul by plane to the Bosnian capital, Sarajevo.

From there, they continued their trip to Germany by car across the so-called Balkan route. Some of them were discovered in the apartments that police searched on Wednesday.

The suspects have mainly Turkish or German citizenships, according to police.