Media reports say the Afghan army is planning a major counter-attack today to drive the Taliban out of Lashkargah, the capital of Helmand province, warning residents they must immediately flee their homes.

France 24 says dozens of civilians have already died in the battle for Lashkargah that would be the Taliban's biggest urban prize since the insurgents launched a nationwide offensive in May.

The Taliban have reportedly taken control of vast swathes of the countryside and key border towns as they have rushed to fill the vacuum left by withdrawing US forces.

Al Jazeera reported yesterday that fighting is raging for Lashkargah with the United Nations saying at least 40 civilians were killed in the last 24 hours.

General Sami Sadat, commander of the 215 Maiwand Afghan Army Corps, told residents on Tuesday to get out as soon as they could.

“Please leave as soon as possible so that we can start our operation,” he said in a message to the city of 200,000 delivered via the media, according to Al Jazeera.

The BBC says there are reports that Taliban fighters have taken positions inside homes, shops and the bazaar - people are trapped in their homes while fighting goes on in the streets.

The UN says civilians are bearing the brunt of the conflict and is urging all parties to do more to protect civilians or the impact will be catastrophic.

The Taliban have seized control of much of rural Afghanistan since foreign forces began the last stage of their withdrawal in May, but are now focused on capturing provincial capitals, where they are meeting stiffer resistance.