BAGHDAD — Iraqi Shi’ite cleric Muqtada al-Sadr, whose coalition won the largest number of seats in last month’s parliamentary elections, has announced an alliance with an Iran-backed coalition ahead of marathon negotiations to form a new government.

The move, announced by Sadr and Hadi al-Amiri of the Fatah coalition in the southern Shi’ite city of Najaf, came largely as a surprise as Sadr has been touting himself as a nationalist leader who opposes Iranian influence in Iraq.

The new alliance controls 101 seats, still far from the 165 required for a majority.

At a news conference Tuesday, both leaders underscored that their alliance is aimed at expediting the formation of a new government and they called on others to join them.

‘‘We had a very positive meeting in order to end the suffering of the country and the people,’’ Sadr said. ‘‘Our new alliance is a nationalist one and within the national frames.’’

In the years following the US-led invasion that toppled Saddam Hussein, Sadr led militiamen who fought US troops in Iraq. Then they were backed by Iran, but in recent years the cleric presented himself as a nationalist leader opposed to Iranian influence.

His Sa’eroun alliance, which also includes the Communist Party and secular candidates, won 54 seats, followed by Fatah, a coalition of Shi’ite paramilitaries who fought the Islamic State group in past years, with 47 seats.

associated press