Iraqi Prime Minister Adel Abdul-Mahdi announced Friday he would resign after more than 40 anti-government protesters were killed by security forces a day earlier, as deadly confrontations between demonstrators and authorities continue across Baghdad and southern Iraq.

The move comes 13 months after Abdul-Mahdi, 77, took office, which triggered celebrations by anti-government protesters who’ve called for reforms to root out corruption, fix the country’s high employment and improve public services.

“I will submit to parliament an official memorandum resigning from the current prime ministry so that the parliament can review its choices,” he said in a statement.

He was appointed Iraq’s fifth prime minister following the 2003 U.S.-led invasion that toppled Saddam Hussein.

Iraq’s top Shiite cleric, the Grand Ayatollah Ali al-Sistani, also called for lawmakers to withdraw their support for the prime minister.

Abdul-Mahdi said he “listened with great concern” to al-Sistani and made his decision in response to his call and in order to “facilitate and hasten its fulfillment as soon as possible.”

On the street near Baghdad’s packed Tahrir Square, people celebrated with caution.

“The political system will replace him with someone exactly the same,” said Taif, a 39-year-old protester. “Until this sick system is destroyed, we won’t leave.”

Another named Mortada, 21, said protesters want electoral reforms and “real change.”

“It’s not one man, it’s the whole system that needs to resign,” he said.

Both Taif and Mortada declined to give them full names for fear of retaliation.

Nearly 400 people have been killed since protestsbroke out nearly two months ago amid widespread dissatisfaction with the government. If accepted when put to a vote, Abdul-Mahdi would be the second Arab leader to be forced out by mass protests in recent months.

Saad Hariri resigned as Lebanon’s prime minister on Oct. 29, which has resulted in gridlock and uncertainly in that country’s political system.