NAJAF, Iraq — Prime Minister Adel Abdul Mahdi of Iraq formally submitted his resignation to Parliament on Saturday and asked lawmakers in a televised national address to quickly agree on a successor.

But Mr. Mahdi’s resignation may not spell the end of the turmoil that has racked the nation over the past two months. Parliament, which met on Sunday and voted to accept his resignation, has yet to agree on an alternative.

“The resignation of the government is a method of peaceful handover of power in democratic systems,” Mr. Mahdi said in his brief speech, adding that the government had tried to meet the demands of the country’s widening protest movement.

Protests driven by anger over political corruption and Iran’s influence over Iraqi politics — coupled with the government’s violent response — had put Mr. Mahdi under intense pressure to step down. At least 400 people have been killed in the unrest, according to the United Nations and hospital sources.