New coalition increases the chances of forming a government after weeks of political tensions following May vote.

Iraqi Prime Minister Haider al-Abadi and Shia leader Muqtada al-Sadr have announced that their blocs are joining forces in a bid to create a new government after weeks of political tensions following last month’s parliamentary elections.

Sadr’s Sairoon Alliance won 54 seats in the May vote to become the largest bloc in Iraq’s 329-seat parliament, while Abadi’s alliance – once seen as a frontrunner – came in third, with just 42 seats.

After a three-hour meeting on Saturday in the Shia holy city of Najaf, the two men issued a joint statement announcing they had set up a coalition.

The statement said their alliance “transcends sectarianism and ethnic” issues “in order to speed up the formation of the new government and agree on the principles which serve the aspirations of our people”.

“We announce a cross-sectarian, cross-ethnic alliance to speed up forming the next government and to agree on common points that guarantee the interests of the Iraqi people,” Sadr said at a news conference after the meeting.

Sadr, who once led violent campaigns against the US occupation that ended in 2011, has emerged as a nationalist opponent of powerful Shia parties allied with neighbouring Iran and as a champion of the poor.

He called for a wider alliance consisting of all components of Iraqi society that would form an inclusive government.

The May 12 vote was marred by historically low turnout and fraud allegations.

Triple alliance?

The joint statement did not mention an alliance al-Sadr formed earlier this month with the pro-Iranian former fighters under Hadi al-Amiri, whose list came second in the election with 47 seats.

There was no immediate reaction from al-Amiri’s camp, but al-Abadi said his pact with al-Sadr would not compromise the Shia leader’s other alliance.

“I affirm that this alliance is not in contrast to any other alliances either of the two lists have previously entered into with other blocs, rather, it flows in the same direction and same principles,” said the prime minister

The top three winning blocs, all Shia-led, have upwards of 140 seats between them. At least 165 seats are needed to form a government although traditionally the ruling bloc in parliament tends to be larger so as to include Sunni Arab and Kurdish politicians.

Al-Sadr’s alliance comprising of communists and secular Iraqis has announced it is fiercely opposed to any foreign interference in Iraq – whether Tehran’s or Washington’s.

Amiri is Iran’s closest ally in Iraq, having spent two years in exile there during the era of former President Saddam Hussein.

Bill Law, a journalist with years of experience in covering Iraqi politics, said the coalition between the leading three political figures “needs to work for the sake of Iraq”.

“It’s been a really extraordinary journey for al-Sadr,” he told Al Jazeera.

“A little more than 10 years ago, his Mahdi Army was killing and ambushing American soldiers in Iraq and now he is the kingmaker after an election that had a very low turnout and was marred by many allegations of irregularities – and yet he has been able to pull together the Shia-supported al-Amiri and to bring al-Abadi and his bloc into this broader coalition.”

Talks to form a new government are expected to continue for weeks or months.