Making a rare intervention in politics, Sistani in his weekly sermon that Iraqis should "avoid falling into the trap of those ... who are corrupt and those who have failed, whether they have been tried or not".

Sistanisaid he was keeping an "equal distance" from all candidates and did not identify any of them by name in his sermon, which was read by one of his representatives, Sheikh Abdel-Mehdi al-Karbalai, and broadcast on television, The daily star reported.

But the reference to Maliki was clear from his mention of the collapse of security forces in the face of IS militants in 2014, when Maliki was in power.

"Past electoral experiments were marked by failures, many of those who were elected or appointed to high positions in the government abused their power and took part in spreading corruption and squandering public money," Sistani also said.

The May 12 election is shaping up as a three-man contest between Abadi, Maliki and Hadi al-Amiri.

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