Berlin - German police hunting evidence of kickbacks have raided offices of Ferrostaal, a German engineering company, Munich prosecutors said Wednesday.

A German television channel said mysterious payments, possibly of up to 4 million euros (5.5 million dollars), to an enterprise in the Arabic-speaking world were a key part of the inquiry.

A Munich prosecutor said three persons had been detained and offices were searched in five cities, but declined further information, saying the raids were ongoing.

The inquiry is a spillover from a hunt at the MAN company for bribes paid to public officials in several nations for choosing MAN- brand buses for municipal fleets.

Ferrostaal, in which MAN group currently has a 30-per-cent stake, was under the spotlight in connection with sales of tugboats by its Muetzelfeld Dockyard in Cuxhaven on Germany's North Sea coast, Bavarian TV said.

A TV report said the Arab recipient had never supplied parts or work in constructing eight ocean-going tugs for a Hamburg salvage company, Harms, yet had received nearly 500,000 euros per tug.

Bavarian TV said it was told the investigators suspected 15 million euros (21 million dollars) in kickbacks were involved.

MAN declined comment. Ferrostaal-Sprecher told Bavarian TV it would not comment till it had checked its records.

MAN earlier in the day issued a report by its own investigation team from the law firm WilmerHale saying the scale of illegal commissions MAN's vehicles division had been small and they had only occurred up to and in 2006. (dpa)