Authorities in Iraq have shut down the country's largest oil refinery after tanker drivers stopped work because of death threats. 

The threats were in response to a steep rise in the price of petrol earlier this month, which provoked widespread protests. 

The closure of the terminal north of Baghdad is expected to cause fuel shortages and problems with electricity supply.

An Oil Ministry spokesperson said the closure was costing Iraq more than €16 million a day in lost revenue.

Iraq's oil exports have also been hit by bad weather in the south of the country and a sabotage attack in the north.

Stormy conditions forced loadings at the Basra terminal in the Gulf to be halted, while an explosion damaged a pipeline to the Mediterranean Sea.

Earlier it emerged that 25 Shi'ites had been killed in two separate attacks south of Baghdad.

14 Iraqis, men and women, were machine-gunned while travelling in a minibus on a small road in Latifiyah, 40km from the capital.

Those killed were Shi'ites from nearby Mahmudiyah who reportedly left their home Thursday morning and whose bodies were found later in the day.

Also in Latifiyah, 11 members of a Shi'ite family were killed when six assailants slit their throats after breaking into their house.

Police said the family had been warned by insurgents to move out of the largely Sunni district, but had not done so.

And in Baghdad, four policemen were killed and five others wounded when a suicide bomber wearing a police uniform blew himself up at a check point near the Ministry of Interior.