Targeting the Boston Marathon was "all the more appalling for taking place at an event renowned for bringing people together from around the world in a spirit of sportsmanship and harmony", he added.

BBC: Boston blasts: World reaction

The greatest challenge facing the contemporary Muslim world is to bring our limited, human understanding of Islamic law into harmony with its divine spirit -- in order to reflect God's mercy and compassion, and to bring the blessings of peace, justice and tolerance to a suffering world.

CENTERFORSECURITYPOLICY: Warrior of ideas