Iraq’s top Shiite cleric urged unity today after Nouri al-Maliki agreed to step down as prime minister, reviving hopes for a new government that can take on Sunni insurgents who have overrun large parts of the country.

Al-Maliki announced he was giving up his post on national television late Thursday, standing alongside senior members of his Shiite Islamic Dawa Party, including his rival and premier designate Haider al- Abadi.

The move paves the way for the country’s first democratic transfer of power since U.S. troops withdrew at the end of 2011 and comes amid widespread calls for a more inclusive government that can reach out to Sunnis and Kurds and stitch the country back together.

Today, Iraq’s most revered Shiite cleric, Ayatollah Ali al-Sistani, called upon the next government to address “shortcomings” in security and to crack down on corruption in the political establishment. He said there is a “dire need” for new leadership that can combat terrorism and heal sectarian divisions.

“This is a rare, positive chance for Iraq to pursue new horizons that will lead to solving all of its problems — especially political and security,” the reclusive leader said in a sermon delivered today by his spokesman Ahmed al-Safi in the holy city of Karbala.

“The enormous spread of corruption in state institutions hampers any real progress in the sectors of security, services and economic development.”

Al-Sistani, who rarely appears in public and almost always delivers messages through spokesmen, had been issuing veiled calls for al-Maliki to step aside for weeks, marking a rare intervention in politics by the normally quietist cleric.

Al-Maliki’s decision to stand down defused a crisis that had hindered the government’s ability to combat the extremist Islamic State group, which captured vast swaths of western and northern Iraq — including the country’s second largest city Mosul — in June.

Iraq’s armed forces in Sunni-majority areas collapsed in the face of the militant onslaught, with much of the blame falling on al-Maliki, whom critics said had staffed the military’s officer corps with incompetent loyalists and aggravated sectarian tensions by marginalizing the country’s once dominant Sunni minority.

Al-Maliki said he was stepping aside in favor of his “brother” al-Abadi in order to “facilitate the political process and government formation.”

Al-Abadi, a veteran Shiite lawmaker, now faces the immense challenge of trying to unite Iraqi politicians as he tries to cobble together a Cabinet over the next 30 days. The country’s major political factions deeply distrust each other and the army has thus far proved incapable of taking back territory.

Al-Maliki had been struggling for weeks to stay on for a third four-year term, and had vowed to challenge the selection of al-Abadi in court. Military tanks and Humvees had deployed across Baghdad over the past week, raising fears of a coup.

But the increasingly isolated al-Maliki eventually stood down, calling on the armed forces to stay out of politics and eventually agreeing to step aside.

The United States, the U.N. and a broad array of political factions in Iraq, including many of al-Maliki’s erstwhile Shiite allies, had backed al-Abadi. Regional rivals Iran and Saudi Arabia, normally fiercely divided over Iraq, were in rare agreement that al-Maliki should go.

The White House commended al-Maliki’s move and expressed hope that the transfer of power “can set Iraq on a new path and unite its people” against the threat from Islamic militants, national security adviser Susan Rice said in a statement.

U.S. Secretary of State John Kerry said the move “sets the stage for a historic and peaceful transition of power in Iraq.”