Berlin  - Germany plans to ask Kenya to take custody of nine pirates captured earlier this week by the German Navy off the coast of Somalia, a Foreign Ministry spokesman said Sunday.

Prosecutors in the German city of Hamburg issued arrest warrants for the nine Somalis on Friday, but a day later said there was no need for them to be transferred to Germany.

The Foreign Ministry spokesman said the request for Kenya to take custody of the pirates would formally be made to authorities in Nairobi by the German embassy on Monday.

Germany's government had been seeking the transfer of the suspects to Kenya, a move that was sealed Friday morning in an agreement with the European Union.

The frigate Rheinland-Pfalz, where the pirates have been held since March 3, is due to arrive in the Kenyan port of Mombasa on Tuesday, when the handover is expected to take place.

The frigate, which forms part of the EU's anti-piracy mission Atalanta, apprehended the pirates when they attacked a German merchant vessel off Somalia with anti-tank missiles and firearms.

According to the EU regulations the mission is operating under, pirates can be held for 12 days.

The EU-Kenya agreement was signed in Nairobi by Kenyan Foreign Minister Moses Wetang'ula and the Czech ambassador to Kenya. The Czech Republic is the current chair of the EU.

Kenya is a neighbouring country to Somalia, where many of the pirates operating in the Gulf of Aden are from. In 2008, pirates seized more than 200 ships off the Somali coast, demanding millions of dollars in ransom. dpa