NAIROBI, May 10 (Xinhua) -- Armed pirates have hijacked a merchant ship of the United Arab Emirates (UAE) off the coast of Somalia , holding an unknown number of crew hostage, Kenya's maritime official said on Thursday.

    Andrew Mwangura, coordinator of the Mombasa-based Seafarers Assistance Program (SAP) said the UAE general cargo ship was hijacked last Thursday and taken to Hobyo, about 400 km northeast of Mogadishu.

    "Somali pirates are holding captive a United Arab Emirates general cargo ship. The vessel was hijacked 10 miles (about 16 km)north of Mogadishu ," Mwangura told Xinhua by telephone from Mombasa.

    He said negotiations were underway for the release of the ship,which is the latest in a growing number of hijackings since the beginning of this year.

    Mwangura said neither the flag of the vessel nor the number and nationalities of the crew was yet known.

    "We have no details of the hijack. We still don't know how many crew members were onboard and the name of the vessel but negotiations is currently underway for the release of the ship,"said Mwangura.

    He said the new wave of attacks has badly shaken merchant shipping, which relies heavily on key international trade routes that snake down Somalia 's coastline, Africa's longest.

    Piracy is rampant in Somalia and the latest hijacking was the fourth reported since the interim government and its Ethiopian allies routed Islamists from Mogadishu.

    The global maritime body warned that the Horn of African nation's coastline is one of the most dangerous in the world.