Bangladesh, June 3 -- Iraqs campaign against corruption entered a dramatic new phase this week following the arrest of a senior oil official accused of involvement in large-scale financial misconduct. Authorities say the detention of Deputy Oil Minister for Refining Affairs Adnan Mohamed Mahmoud led to the discovery of an extraordinary cache of cash, gold, properties, and military-grade weapons, highlighting the scale of alleged corruption within one of the countrys most important economic sectors.

The arrest has become one of the most significant anti-corruption actions undertaken in Iraq in recent years and is being viewed as a major test of the governments commitment to tackling entrenched graft. Officials and lawmakers have described...