Somali pirates have struck again in the Gulf of Aden.A Greek-owned cargo ship with 22 crew on board has been seized. The vessel is loaded with coal and was on its way to Slovenia. The latest capture comes despite the boosted presence of numerous navies in the region. The pirates have earned millions of euros in ransom payments, pushing up maritime insurance rates. A Saudi oil supertanker was among dozens of vessels seized last year. Experts warn that pirates are stepping up their attacks after a lull in December and January, adding that ship captains should maintain a 24-hour watch.