BAGHDAD (Reuters) - Iraq’s parliament on Thursday postponed questioning acting Trade Minister Salman al-Jumaili over corruption allegations after he launched a legal challenge, trade ministry officials and parliament sources said.

The minister, a Sunni Muslim in a government dominated by Shi’ites, contested the legality of the signatures gathered to authorize his grilling, one of the lawmakers leading the investigation said.

The lawmaker, Alia Nussayif, said the case that included import deals for contaminated rice would now be considered in parliament on Aug. 7.

Jumaili has denied any wrong doing. His media adviser said on Thursday some of the signatures had been forged.

“Minister Jumaili is ready to answer all questions but the process should be legal and valid,” Abdul Zahra al-Hindawi said in a statement.

Prime Minister Haidar al-Abadi has promised to tackle corruption in a political system that doles out positions along ethnic and sectarian lines, creating powerful patronage networks.