Insurgents in Iraq have carried out another attack on the country's infrastructure, hitting Baghdad's main oil refinery with mortar fire.

The attack late Thursday, ignited a fire at the Dura refinery, which feeds a power plant that provides electricity to the capital and surrounding areas.  Repeated insurgent attacks on the refinery have contributed to fuel shortages in Baghdad and the surrounding region.  Electrical power service in Baghdad also is very erratic, often operating for only a few hours each day.

There is no word who shelled the refinery, but, hours earlier, three radical groups issued another warning that they intend to attack anyone who takes part in Iraq's national elections, still scheduled to take place at the end of January.

The militant group Ansar al-Sunna and two other insurgent groups said in a statement that they oppose the elections because, in their view, democracy is unIslamic.

A translation by Associated Press of the groups' message, as posted on an Internet site, said:  "Democracy is a Greek word meaning the rule of the people, which means that the people do what they see fit."  The militant groups' message added that "this concept is considered apostasy and defies the belief in one God, Muslims' doctrine." 

Some information for this report provided by AFP, AP and Reuters.