By Jonathan Saul LONDON (Reuters) -A Spanish navy ship is sailing at full speed towards a Maltese-flagged commercial vessel that may have been hijacked by pirates off Somalia, the European Union’s Somali counter piracy force said on Friday. If confirmed, it would be the first successful hijacking involving Somali pirates since 2017 when a crackdown by international navies stopped a rash of seizures in the Gulf of Aden and the Indian Ocean. EUNAVFOR’s joint operations centre in Spain said it received an alert on Thursday about the “alleged pirate-hijacked vessel” Ruen, which was approximately 5…