After Iraq gains, Qaeda offshoot claims Islamic 'caliphate'

BEIRUT (Reuters) - An offshoot of al Qaeda which has seized territory in Iraq and Syria has declared itself an Islamic "caliphate" and called on factions worldwide to pledge their allegiance, a statement posted on Islamist websites and Twitter said on Sunday.

The move poses a direct challenge to the central leadership of al Qaeda, which has disowned it, and to conservative Gulf Arab rulers who already view the group as a security threat.