Marines pushed deeper into Taliban strongholds today after suffering the first fatality of their massive offensive against Afghanistan’s hardline Islamist militia.

Ferried in by relays of helicopters Thursday, Marines were on the ground in Helmand province’s districts of Garmsir and Nawa, and also helped Afghan forces take Khanishin, towards the border with Pakistan, officers said.

“Today Marines are continuing to move towards those objectives that are still out there and they are going to work to stabilise security in these areas,” spokesman First Lieutenant Kurt Stahl said today.

The nearly 4,000 Marines are spearheading President Barack Obama’s aggressive new war plan for Afghanistan’s bloody insurgency with an emphasis on protecting the population ahead of presidential elections on August 20.

“When Marines go out into towns, they are always looking for opportunities to talk to village elders and explain why they are here,” Stahl said.

“The intention is to understand each other, elders can express their concerns and an open flow of communication is secured.”

On Thursday troops quickly overran Khanishin district, where the Taliban had set up a proxy government and justice system, within hours of the launch of the Marines’ biggest operation since Fallujah in Iraq in November 2004.

But they also recorded their first death in an air and land assault that is one of the biggest joint campaigns in post-Taliban Afghanistan.

“One Marine has been killed in action, and several others have been injured or wounded throughout the day,” a statement said. There was no confirmation of civilian casualties or damage to property, it said.

Stahl said late Thursday that helicopters had put all troops on the ground in Garmsir and Nawa, districts that are key targets of the desert assault.

But the Taliban reportedly dismissed the mobilisation, with the Afghan Islamic Press quoting a spokesman as saying that previous military operations in vast and rugged Helmand had not yielded success for the armed forces.

“We are resisting but would adopt all kinds of war tactics to the situation,” spokesman Yousuf Ahmadi was quoted as telling the agency.

Taliban’s hardline Haqqani faction claimed it was holding a U.S. soldier who had been missing since June 30, before the current offensive kicked off.

“We are using all of our available resources to find him and provide for his safe return,” U.S. military spokeswoman Captain Elizabeth Mathias told AFP, declining to go into further detail.

Called Khanjar, which means “dagger” in Dari and Pashtu but was translated by the Marines as “Strike of the Sword”, the new U.S. offensive also involves about 600 Afghan police and soldiers.

“What makes Operation Khanjar different from those that have occurred before is the massive size of the force introduced, the speed at which it will insert,” Marine commander Brigadier General Larry Nicholson said Thursday.

The forces pushed south down the Helmand River valley, deep into insurgent-held areas where foreign troops have failed to establish a presence despite ousting the Taliban from power nearly eight years ago.

Commanders said they would persuade locals that the Afghan security forces — backed by Western troops — offered them a better long-term future than the fundamentalist militia.

Afghan army corps commander General Shair Mohammad Zazai told AFP the operation would establish security “so that people can go and vote with confidence and without fear”.

Authorities have fretted that Taliban violence and intimidation could undermine Afghanistan’s second-ever presidential vote, and so set back efforts to move the destitute nation on from its turbulent, war-filled past.