Suicide bomber kills 21 at Saudi Shi'ite mosque, Islamic State claims attack

A family member of a slain victim mourns after arriving at the Imam Ali mosque, the site of a suicide bomb attack, in the village of al-Qadeeh in the eastern province of Gatif, Saudi Arabia, May 22, 2015. REUTERS/Stringer

(This May 22 story has been refiled to fix syntax in second paragraph)

DUBAI (Reuters) - A suicide bomber killed 21 worshippers on Friday in a packed Shi'ite mosque in eastern Saudi Arabia, residents and the health minister said, the first attack in the kingdom to be claimed by Islamic State militants.