A Hezbollah leader has rejected calls to arrest four men accused of assassinating Lebanon’s former prime minster, Rafik Hariri, in 2005.In a televised speech Hasan Nazrallah said no power would be able to arrest the as yet un-named "honourable brothers" accused by a UN court.He added that "each and every void accusation" made by the Special Tribunal for Lebanon was tantamount to an attack on his Shia Islamist group.Wendy Urquhart reports.