A Shi'ite mosque comes under attack in southern Iraq, when a bomb explodes during a service -- wounding six people.br br No one is claiming responsibility for the attack, but Sunni Muslim insurgents have stepped up efforts to undermine Iraq's Shi'ite-led government.br br The bomb exploded in the usually stable oil hub of Basra.br br (SOUNDBITE) (Arabic) EYEWITNESS MAZIN MOHAMMED, SAYING:br br "Six worshippers were wounded by the blast. Some of the injuries are minor, while others were serious. Thank God all the wounded were taken to hospital."br br The attack comes a day after a series of car bombs hit five Shi'ite mosques across Iraq that killed 19 people.