Seven suspected pirates were handed over to the Kenyan authorities by the German marine on Wednesday.
The suspects were arrested on Sunday, said the German marine press relations officer Christoper Kohlmorgan. But neither the Kenyan nor the German authorities were willing to reveal the exact location where the suspects were arrested.
According to Kohlmorgan the pirates were taken captive as they tried to take over a German tanker ship -- Spessart.
"The pirates were arrested when their attempt to hijack a vessel was foiled, "Commander Kohlmorgan told journalists in the coastal city of Mombasa.
Confirming the reports, the port police boss Ayub Ali said the suspects had been detained in cells and would be taken to court. "Their vessel, a fibre skiff and the exhibits they were using at sea which includes AK 47 riffles have also been confiscated," said Ali.
Maritime officials said Greek and Spanish forces from the EU's Atalanta anti-piracy mission off the coast of Somalia captured the men in the Gulf of Aden over a week ago.
The pirates had failed to seize the German supply vessel Spessart. The group was then transferred to the German frigate Rhineland-Pfalz.
The pirates are to be tried in Kenya as part of an agreement with the European Union last month.
The EU and Kenya agreed to transfer to the east African country suspected Somali pirates who are detained as part of the Atalanta mission. Somalia has not had a functioning legal system for years and would be unable to try the pirates.
This is the second time the German Marine vessel delivered pirates to the Kenyan authorities.
The first batch of nine pirates was brought in early last month after being captured in an attempt to hijack a German merchant vessel MV Courier off the Somali coast.
The German frigate is part of the European Union's anti-piracy mission in the Gulf of Aden and started delivering pirates to the Kenyan authority following an agreement with EU countries on March 6, to have suspects arrested in the Gulf of Aden tried in the country.
Earlier, Kenya received seven suspected Somali pirates captured by the US Navy.