Protesters chant anti-government slogans as riot police guard the provincial council building during a rally against corruption and the lack of government services in Basra, of Baghdad, on Friday. (Nabil Al-Jurani/AP)

Iraq’s prime minister announced drastic anti-corruption and other measures on Sunday as he sought to calm weeks of protests over poor government services that are posing a major challenge to his rule.

In statements posted to his official Facebook and Twitter accounts, Prime Minister Haider al-Abadi said his government would reopen graft cases under the supervision of a high-level commission, change the way ministers are selected by eliminating party- and sectarian-based quotas, and end expensive security details for senior officials.

“We are starting today genuine reform in all areas,” Abadi said in a statement.

The most dramatic step was his pledge to immediately abolish the country’s three vice-presidential posts, considered largely ceremonial, as well as the office of deputy prime minister.

Nouri al-Maliki, Abadi’s predecessor and political rival, serves as a vice president but is thought to still wield considerable in­fluence. Deputy Prime Minister ­Bahaa al-Araji, who is under investigation over corruption allegations, resigned Sunday after the announcement.

But it was unclear whether Abadi would need a constitutional amendment to eliminate the vice presidencies. Some of the measures, Iraqi legal experts said, would need approval from both the cabinet and parliament. Opposition blocs in parliament are likely to push back against the decree.

“Some blocs will try to obstruct the vote on this resolution because it threatens their interests,” lawmaker Hamid al-Mutlak said. “But public pressure is very strong.”

Iraqi media reported Sunday that the cabinet endorsed the measures. The speaker of parliament, Salim al-Jubouri, said Sunday that he supports the package.

Moqtada al-Sadr, a powerful Iraqi Shiite cleric who once helped lead an insurgency against U.S. troops, released a statement Sunday calling on “millions” to protest if parliament refuses to ratify the proposals.

“Everyone should stand against the corrupt,” he said.

Many Iraqis blame Maliki, who was prime minister from 2006 to 2014, for the corruption that has plagued the country’s political life since the 2003 U.S.-led invasion installed a new system of government. On Friday, tens of thousands of Iraqis demonstrated across the country and here in the capital against leaders who they say have plundered public wealth and neglected Iraq’s war-battered infrastructure.

The protests, which began last month in southern Iraq and have spread, came amid a searing heat wave in which temperatures have topped 120 degrees. The heat has been particularly unbearable because of the limited power supply in the country, giving Iraqis only a few hours’ worth of electricity a day to run fans or air conditioners.

On Sunday, activists called for more demonstrations in central Baghdad to support Abadi’s initiatives, even in the 110-degree heat.

The country’s powerful Shiite militias — whose political influence has grown as they overtake the Iraqi army in the fight against the Islamic State — also threw their weight behind Friday’s protests. Their participation presented an unusual challenge to Abadi from his own Shiite constituency.

The demonstrations prompted the office of influential Shiite religious leader Grand Ayatollah Ali Sistani to call for tough measures. Sistani said Friday that Abadi had not done enough to fight corruption within the Iraqi state.

The unrest presents a new challenge for a government embroiled in a battle with Islamic State militants, who have seized wide swaths of the country and displaced more than 3­ million people since last year. More than 1,300 Iraqis were killed in the violence last month, the United Nations said. On the battlefield, entire police and army divisions have crumbled in the face of Islamic State onslaughts.

Independent military expert Mohamed Arkan said Abadi’s decision to eliminate the excessive security details for senior officials and divert those troops for front-line training was a positive step.

It means the potential addition of “tens of thousands” of soldiers to the fight against the militant group, Arkan said.

Cunningham reported from Beirut.

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