LEADING Iraqi Shi'ite cleric Grand Ayatollah Ali al-Sistani urged the country’s political blocs today to agree on a new prime minister before the newly elected parliament sits next week.

His intervention steps up pressure on political leaders to set aside their differences and form an inclusive government in the face of religious extremists who have seized large swathes of territory.

Ayatollah al-Sistani also wants the politicians to agree on a speaker and president by the time the new legislature meets on Tuesday, his representative Abdul-Mahdi al-Karbalaie told worshippers in the holy city of Karbala.

The cleric stressed that selecting the three top leaders before parliament meets would be a “prelude to the political solution that everyone seeks.”

Shi'ite leaders are pushing for the removal of current PM Nouri al-Maliki, whose bloc won most seats in April’s elections — 92 out of the legislature’s 328 — but who has been widely accused of centralising power and alienating Sunnis with a heavy-handed response to years of militant violence.

Even Mr Maliki’s most important ally, Iran, is believed to be looking at alternatives.

US-based Human Rights Watch said yesterday that the extremists, led by the Islamic State of Iraq and the Levant (Isis) slaughtered at least 160 captive soldiers earlier this month. 

The group based its findings on satellite imagery and grisly photos released by Isis, corroborating earlier accounts of a massacre and saying that the actual toll could be far higher.

Isis is believed to have released evidence of its own atrocity to demoralise Iraqi troops.

An Iraqi military official announced yesterday that 200 government troops had arrived at the key Baiji oil refinery north of Baghdad, which has been under attack by militants for more than a week. 

The reinforcements joined a 100-strong contingent that has been defending the refinery, which is Iraq’s largest and the source of about a quarter of the country’s oil needs, including fuel for power stations.

State TV aired footage yesterday purporting to show troops disembarking from helicopters at Baiji, with some carrying boxes of supplies. 

Dense black smoke rose from what appeared to be a large fuel tank.