The number of gunfights appears to be growing Basra gunfight

Heavy fighting has continued for a third day between Shia militias and the Iraqi security forces in southern Iraq.

There are reports of extensive exchanges of fire between the Iraqi army and militiamen in Basra and in the town of Hilla, just south of Baghdad.

More than 70 people have died and hundreds have been injured in days of violence sparked by an Iraqi crackdown on Shia militias in Basra.

There have also been violent clashes in Kut and the capital, Baghdad.

On Wednesday, Iraqi Prime Minister Nouri Maliki gave Shia militants in Basra 72 hours to lay down their arms or face “severe penalties”.

The leader of the Mehdi Army, Shia cleric Moqtada Sadr, has spoken of the possibility of negotiations to end the violence.

Gunfights

In Basra, police chief Adbul Jalil Khalaf said he survived an assassination attempt overnight, in which three of his bodyguards were killed.

Residents in the city have said that they are beginning to run out of food and water.

One told the BBC that the Iraqi army broke into shops, took food and water, then set fire to shops and cars on the street.

BASRA KEY FACTS Third largest city, population 2.6 million approx Located on the Shatt al-Arab waterway leading to the Gulf – making it a centre for commerce and oil exports Region around city has substantial oil resources 4,000 UK troops based at international airport The struggle for Basra Life under fire Oil soars above $107

“I am trying to look out of the window now, but I can’t – the smoke’s really heavy and smells really bad. Everything is burnt,” he said.

An oil pipeline near Basra, which carries oil for export, was damaged by a bomb.

A Southern Oil Company official told the Reuters news agency that the main pumping station of Zubair 1 was shut down and that exports would be greatly affected.

“Firefighters are struggling to control the fire, which is huge. A lot of crude has spilt onto the ground… We will not be able to repair it unless security is provided for the crews,” he said.

In other developments across the country:

Power struggle

The number of gunfights in southern Iraq appears to be growing, says the BBC’s Crispin Thorold in Baghdad.

The fighting still seems to be mainly with members of the Mehdi Army, our correspondent says.

Baghdad’s Green Zone has been targeted by insurgents again

The Medhi Army had held to a ceasefire since last August, contributing to the general fall in violence across Iraq.

It is not clear what has prompted the government crackdown at this time. The government says its campaign aims to re-impose law and order in Basra.

However, Sadrists say the government is attempting to weaken the militias before local elections scheduled for October.

At stake, analysts say, is control of Iraq’s only port city and the region’s oil fields.